Toán tử Matlab trong Python

Thay đổi bố cục cửa sổ mặc định trong Spyder

Cửa sổ mặc định trong Spyder trông như hình bên dưới. Đây là phiên bản 3. 3. 4 của Spyder chạy trên Windows 10. Nó sẽ trông khá giống trên macOS hoặc Linux

Trước khi xem qua giao diện người dùng, bạn có thể làm cho giao diện trông giống MATLAB hơn một chút. Trong menu View → Window layouts chọn MATLAB layout. Điều đó sẽ tự động thay đổi cửa sổ để nó có cùng các khu vực mà bạn đã sử dụng từ MATLAB, được chú thích trên hình bên dưới

Ở trên cùng bên trái của cửa sổ là File Explorer hoặc danh sách thư mục. Trong khung này, bạn có thể tìm thấy các tệp mà bạn muốn chỉnh sửa hoặc tạo các tệp và thư mục mới để làm việc với

Ở trung tâm trên cùng là trình chỉnh sửa tệp. Trong trình chỉnh sửa này, bạn có thể làm việc trên các tập lệnh Python mà bạn muốn lưu để chạy lại sau này. Theo mặc định, trình chỉnh sửa sẽ mở một tệp có tên

In [2]: import antigravity

Ở trung tâm dưới cùng là bảng điều khiển. Giống như trong MATLAB, bảng điều khiển là nơi bạn có thể chạy các lệnh để xem chúng làm gì hoặc khi bạn muốn gỡ lỗi một số mã. Các biến được tạo trong bảng điều khiển sẽ không được lưu nếu bạn đóng Spyder và mở lại. Bảng điều khiển về mặt kỹ thuật chạy IPython theo mặc định

Bất kỳ lệnh nào bạn nhập vào bảng điều khiển sẽ được ghi vào tệp lịch sử ở ngăn dưới cùng bên phải của cửa sổ. Furthermore, any variables that you create in the console will be shown in the variable explorer in the top right pane

Notice that you can adjust the size of any pane by putting your mouse over the divider between panes, clicking, and dragging the edge to the size that you want. You can close any of the panes by clicking the x in the top of the pane

You can also break any pane out of the main window by clicking the button that looks like two windows in the top of the pane, right next to the x that closes the pane. When a pane is broken out of the main window, you can drag it around and rearrange it however you want. If you want to put the pane back in the main window, drag it with the mouse so a transparent blue or gray background appears and the neighboring panes resize, then let go and the pane will snap into place

Once you have the panes arranged exactly how you want, you can ask Spyder to save the layout. Go to the View menu and find the Window layouts flyout again. Then click Save current layout and give it a name. This lets you reset to your preferred layout at any time if something gets changed by accident. You can also reset to one of the default configurations from this menu

Running Statements in the Console in Spyder

In this section, you’re going to be writing some simple Python commands, but don’t worry if you don’t quite understand what they mean yet. You’ll learn more about Python syntax a little later on in this article. What you want to do right now is get a sense for how Spyder’s interface is similar to and different from the MATLAB interface

You’ll be working a lot with the Spyder console in this article, so you should learn about how it works. In the console, you’ll see a line that starts with

In [2]: import antigravity

One of the first things I like to do with folks who are new to Python is show them the Zen of Python. This short poem gives you a sense of what Python is all about and how to approach working with Python

To see the Zen of Python, type

In [2]: import antigravity

>>>

In [1]: import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

This code has

In [2]: import antigravity

In [2]: import antigravity

In many of the code blocks in this article, you’ll see three greater-than signs [

In [2]: import antigravity

Many Pythonistas maintain a healthy sense of humor. This is displayed in many places throughout the language, including the Zen of Python. For another one, in the Spyder console, type the following code, followed by Enter to run it.

>>>

In [2]: import antigravity

That statement will open your web browser to the webcomic called XKCD, specifically comic #353, where the author has discovered that Python has given him the ability to fly

You’ve now successfully run your first two Python statements. Congratulations 😃🎉

If you look at the History Log, you should see the first two commands you typed in the console [

In [2]: import antigravity

In [2]: import antigravity

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, you defined 3 variables.

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

There are two main things for you to notice in these commands

1. If a statement does not include an assignment [with an

   In [2]: import antigravity
   

   63], it is printed onto an

   In [2]: import antigravity
   

   60 line. In MATLAB, you would need to include a semicolon to suppress the output even from assignment statements, but that is not necessary in Python

2. On input lines 3, 4, and 5, the Variable explorer in the top right pane updated

After you run these three commands, your Variable explorer should look like the image below

Trong hình ảnh này, bạn có thể thấy một bảng có bốn cột

1. Name shows the name that you gave to

   In [2]: import antigravity
   

   51,

   In [2]: import antigravity
   

   52, and

   In [2]: import antigravity
   

   53
2. Type shows the Python type of the variable, in this case, all

   In [2]: import antigravity
   

   68 for integer numbers
3. Size shows the size of the data stored variable, which is more useful for lists and other data structures
4. Value shows the current value of the variable

Running Code in Files in Spyder

The last stop in our brief tour of the Spyder interface is the File editor pane. In this pane, you can create and edit Python scripts and run them using the console. By default, Spyder creates a temporary file called

In [2]: import antigravity

Let’s write some code into the

In [2]: import antigravity

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

In this code, you can see two Python syntax structures

• Line 1 has a comment. In Python, the comment character is the hash or pound sign [

  In [2]: import antigravity
  

  71]. MATLAB uses the percent symbol [

  In [2]: import antigravity
  

  72] as the comment character. Anything following the hash on the line is a comment and is usually ignored by the Python interpreter

• Starting on line 2 is a string that provides some context for the contents of the file. This is often referred to as a documentation string or for short. You’ll learn more about docstrings in

Now you can start adding code to this file. Starting on line 8 in

In [2]: import antigravity

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

Then, there are three ways to run the code

1. You can use the F5 keyboard shortcut to run the file just like in MATLAB.
2. You can click the green right-facing triangle in the menu bar just above the Editor and File explorer panes
3. You can use the Run → Run menu option

The first time you run a file, Spyder will open a dialog window asking you to confirm the options you want to use. For this test, the default options are fine and you can click Run at the bottom of the dialog box

This will automatically execute the following code in the console

>>>

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

This code will run the file that you were working on. Notice that running the file added three variables into the Variable explorer.

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In Spyder, you can also create code cells that can be run individually. To create a code cell, add a line that starts with

In [2]: import antigravity

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this code, you have created your first code cell on line 11 with the

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

To execute the code cells, click the Run Current Cell or Run Current Cell and Go to the Next One buttons next to the generic Run button in the toolbar. You can also use the keyboard shortcuts Ctrl + Enter to run the current cell and leave it selected, or Shift + Enter to run the current cell and select the next cell.

Spyder also offers easy-to-use debugging features, just like in MATLAB. You can double-click any of the line numbers in the Editor to set a breakpoint in your code. You can run the code in debug mode using the blue right-facing triangle with two vertical lines from the toolbar, or the Ctrl + F5 keyboard shortcut. This will pause execution at any breakpoints you specify and open the

In [2]: import antigravity

In [2]: import antigravity

Summarizing Your Experience in Spyder

Now you have the basic tools to use Spyder as a replacement for the MATLAB integrated development environment. You know how to run code in the console or type code into a file and run the file. You also know where to look to see your directories and files, the variables that you’ve defined, and the history of the commands you typed

Once you’re ready to start organizing your code into modules and packages, you can check out the following resources

• Python Modules and Packages – An Introduction
• How to Publish an Open-Source Python Package to PyPI
• How to Publish Your Own Python Package to PyPI

Spyder is a really big piece of software, and you’ve only just scratched the surface. You can learn a lot more about Spyder by reading the official documentation, the troubleshooting and FAQ guide, and the Spyder wiki

Comments Start With

In [2]: import antigravity

71 in Python

In MATLAB, a comment is anything that follows a percent sign [

In [2]: import antigravity

In [2]: import antigravity

# -*- coding: utf-8 -*-

When the Python interpreter reads this line, it will set the encoding that it uses to read the rest of the file. This comment must appear in one of the first two lines of the file to be valid

Another difference between MATLAB and Python is in how inline documentation is written. In MATLAB, documentation is written at the start of a function in a comment, like the code sample below

function [total] = addition[num_1,num_2]
% ADDITION  Adds two numbers together
%   TOTAL = ADDITION[NUM_1,NUM_2] adds NUM_1 and NUM_2 together
%
%   See also SUM and PLUS

However, Python does not use comments in this way. Instead, Python has an idea called documentation strings or docstrings for short. In Python, you would document the MATLAB function shown above like this

def addition[num_1, num_2]:
    """Adds two numbers together.

    Example
    -------
    >>> total = addition[10, 20]
    >>> total
    30

    """

Notice in this code that the docstring is between two sets of three quote characters [

In [2]: import antigravity

Whitespace at the Beginning of a Line Is Significant in Python

When you write code in MATLAB, blocks like

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

For example, the following two blocks of code are functionally equivalent in MATLAB

In [2]: import antigravity

In this code, you are first creating

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Now you should modify your code so it looks like the sample below

In [2]: import antigravity

In this code, you have only changed lines 3 and 5 by adding some spaces or indentation in the front of the line. The code will perform identically to the previous example code, but with the indentation, it is much easier to tell what code goes in the

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In Python, indentation at the start of a line is used to delimit the beginning and end of class and function definitions,

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In [2]: import antigravity

In addition, in Python the definition line of an

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

In [2]: import antigravity

Consider this code example

In [2]: import antigravity

On the first line, you are defining

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Next, line 3 must be indented in Python’s syntax. On that line, you are using

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

On line 4, you are starting the

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Lastly, on line 6 you are printing a statement from outside the

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Now you should modify the code above to remove the indentation and see what happens. If you try to type the code without indentation into the Spyder/IPython console, you will get an

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

>>>

In [2]: import antigravity

In this code, you first set the value of

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

In [2]: import antigravity

When you’re indenting your code, the official Python style guide called recommends using 4 space characters to represent one indentation level. Most text editors that are set up to work with Python files will automatically insert 4 spaces if you press the Tab key on your keyboard. You can choose to use the tab character for your code if you want, but you shouldn’t mix tabs and spaces or you’ll probably end up with a

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Conditional Statements Use

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

52 in Python

In MATLAB, you can construct conditional statements with

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

You should try this idea out with the code below, and then compare the example of MATLAB vs Python for conditional statements

In [2]: import antigravity

Trong khối mã này, bạn đang xác định

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In Python, the

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

This code block is functionally equivalent to the previous MATLAB code block. There are 2 main differences. On line 4,

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

Calling Functions and Indexing Sequences Use Different Brackets in Python

In MATLAB, when you want to call a function or when you want to index an array, you use round brackets [

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

You can test out the differences in MATLAB vs Python with the example code below

>>>

In [2]: import antigravity

In this code, you first create an array using the square brackets on the right side of the equal sign. Then, you retrieve the value of the first element by

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Python uses separate syntax for calling functions and indexing sequences. In Python, using round brackets means that a function should be executed and using square brackets will index a sequence

>>>

In [2]: import antigravity

In this code, you are defining a Python list on input line 1. Python lists have some important distinctions from arrays in MATLAB and arrays from the NumPy package. You can read more about Python lists in Lists and Tuples in Python, and you’ll learn more about NumPy arrays in

Trên dòng đầu vào 2, bạn đang hiển thị giá trị của phần tử đầu tiên của danh sách với thao tác lập chỉ mục bằng dấu ngoặc vuông. On input line 3, you are calling

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

The First Index in a Sequence Is 0 in Python

In MATLAB, you can get the first value from an array by using

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

>>>

In [2]: import antigravity

In this code, you are creating an array with three numbers.

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In Python, the index of the first element in a sequence is 0, not 1

>>>

In [2]: import antigravity

In this code, you are defining

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

On input lines 4, 5, and 6, you are defining

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

The Last Element of a Sequence Has Index

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

87 in Python

In MATLAB, you can get the last value from an array by using

In [2]: import antigravity

Try out the differences in MATLAB vs Python with this example

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, you are creating an array with three numbers,

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In Python, the last value in a sequence can be retrieved by using the index

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, you are defining a Python list with three elements on input line 1. On input line 2, you are displaying the value of the last element of the list, which has the index

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In fact, by using negative numbers as the index values you can work your way backwards through the sequence

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, you are retrieving the second-to-last and third-to-last elements from the list, which have values of

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Exponentiation Is Done With

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

98 in Python

In MATLAB, when you want to raise a number to a power you use the caret operator [

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 1# -*- coding: utf-8 -*-
 2"""
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 6"""

Try out the differences of MATLAB vs Python with this example

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, you are raising 10 to the power of 2 using the caret resulting an answer of 100

In Python, you use two asterisks [

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, you are raising 10 to the power of 2 using two asterisks resulting an answer of 100. Notice that there is no effect of including spaces on either side of the asterisks. In Python, the typical style is to have spaces on both sides of a binary operator

The Length of a Sequence Is Found With

 1# -*- coding: utf-8 -*-
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05 in Python

In MATLAB, you can get the length of an array with

 1# -*- coding: utf-8 -*-
 2"""
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>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Trong mã này, trên dòng đầu vào đầu tiên, bạn đang tìm độ dài của một mảng có 3 phần tử. As expected,

 1# -*- coding: utf-8 -*-
 2"""
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In Python, you can get the length of a sequence with

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, on the input line 1 you are finding the length of a list with 3 elements. As expected,

 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
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Console Output Is Shown With

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

19 in Python

In MATLAB, you can use

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

 1# -*- coding: utf-8 -*-
 2"""
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 4
 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

Python’s

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, the input lines 1, 2, and 3 define

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

You can control the separator used in the output between arguments to

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, you are printing the same three variables but setting the separator to be a semicolon followed by a space. This separator is printed between the first and second and the second and third arguments, but not after the third argument. To control the character printed after the last value, you can use the

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

>>>

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In this code, you have added the

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Like

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

 1# -*- coding: utf-8 -*-
 2"""
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 4
 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

>>>

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

In this code, input line 7 includes an f-string, indicated by the

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

Input line 9 demonstrates a in Python 3. 8. If a variable name is immediately followed by an equals sign inside curly braces, the name of the variable and the value will be printed automatically

You can take a deep dive into Python’s

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Function Definitions Start With

 1# -*- coding: utf-8 -*-
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45 and

 1# -*- coding: utf-8 -*-
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46 Values in Python

In MATLAB, you can define a function by placing the

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

In [2]: import antigravity

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

In this code, you see the

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 4
 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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In [2]: import antigravity

To use this function in MATLAB, you should save it in a file called

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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>>>

 1# -*- coding: utf-8 -*-
 2"""
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In this code, you have defined two variables called

In [2]: import antigravity

In [2]: import antigravity

 1# -*- coding: utf-8 -*-
 2"""
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 4
 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

 1# -*- coding: utf-8 -*-
 2"""
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MATLAB does not require a function to provide an output value. In this case, you would remove the output variable and the equals sign from the function definition. Modify your

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

 1# -*- coding: utf-8 -*-
 2"""
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The only change in this code from the earlier code is that you deleted the

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

>>>

 1# -*- coding: utf-8 -*-
 2"""
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In this code, you defined the same two variables

In [2]: import antigravity

In [2]: import antigravity

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
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In Python, the

 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
 2"""
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 1# -*- coding: utf-8 -*-
 2"""
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 1# -*- coding: utf-8 -*-
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Starting on the next line, the code that should be executed as part of the function must be indented one level. Trong Python, định nghĩa hàm kết thúc khi một dòng mã bắt đầu ở cùng mức thụt đầu dòng với từ khóa

 1# -*- coding: utf-8 -*-
 2"""
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If your function returns some output back to the caller, Python does not require that you specify a name for an output variable. Instead, you use the

 1# -*- coding: utf-8 -*-
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An equivalent function in Python to your first

 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
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In this code, you see the

 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
 2"""
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 1# -*- coding: utf-8 -*-
 2"""
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 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 6"""

 1# -*- coding: utf-8 -*-
 2"""
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 1# -*- coding: utf-8 -*-
 2"""
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 1# -*- coding: utf-8 -*-
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The variable that stores the sum of

 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
 2"""
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 1# -*- coding: utf-8 -*-
 2"""
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 1# -*- coding: utf-8 -*-
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Line 1 in this code is the same as it was before, you have only changed line 2 and deleted line 3. Line 2 now computes the value of

 1# -*- coding: utf-8 -*-
 2"""
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To use this function in Python, you do not need to save it in a file with a special name. You can place the function definition in any Python file, at any point in the file. There is no restriction that the function definition has to be last. In fact, you can even define functions right from the console, which is not possible in MATLAB

Open Spyder and in the Console pane type

>>>

 1# -*- coding: utf-8 -*-
 2"""
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On this line of code you are creating the function definition. In the Spyder/IPython console, once you start a function definition and press Enter , the start of the line becomes three dots and the cursor is automatically indented. Now you can type the remainder of the function definition. You’ll have to press Enter twice to complete the definition.

>>>

 1# -*- coding: utf-8 -*-
 2"""
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In this code, you have the definition of the function on the first line and the body of the function on the second line. Bảng điều khiển tự động thêm

 1# -*- coding: utf-8 -*-
 2"""
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Khi bạn đã hoàn thành định nghĩa, bạn cũng có thể thực thi chức năng từ bảng điều khiển. You should type this code

>>>

 1# -*- coding: utf-8 -*-
 2"""
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In this code, you first create two variables

In [2]: import antigravity

In [2]: import antigravity

 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
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In Python, if you do not explicitly put a

 1# -*- coding: utf-8 -*-
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 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 1# -*- coding: utf-8 -*-
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>>>

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, you have the same

 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
 2"""
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>>>

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, on input line 7 you are assigning

 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
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 1# -*- coding: utf-8 -*-
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 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 1# -*- coding: utf-8 -*-
 2"""
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 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 1# -*- coding: utf-8 -*-
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 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

Functions Accept Positional and Keyword Arguments in Python

In MATLAB, functions have input arguments specified on the first line, in the

 1# -*- coding: utf-8 -*-
 2"""
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 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, you are defining a function with three possible input arguments. On line 7, you are starting a

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In your code above, you are defining three cases

1. If the number of input arguments is 2, you are adding

    1# -*- coding: utf-8 -*-
    2"""
    3Spyder Editor
    4
    5This is a temporary script file.
    6"""
   

   52 and

    1# -*- coding: utf-8 -*-
    2"""
    3Spyder Editor
    4
    5This is a temporary script file.
    6"""
   

   53 together
2. If the number of input arguments is 3, you are subtracting

    1# -*- coding: utf-8 -*-
    2"""
    3Spyder Editor
    4
    5This is a temporary script file.
    6"""
   

   53 from

    1# -*- coding: utf-8 -*-
    2"""
    3Spyder Editor
    4
    5This is a temporary script file.
    6"""
   

   52
3. If fewer than 2 arguments are passed, the output will be

    8var_4 = 10
    9var_5 = 20
   10var_6 = var_4 + var_5
   

   21

If more than 3 arguments are passed, MATLAB will raise an error

Now you should experiment with this function. Save the code above into a file called

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

>>>

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, you are calling

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

>>>

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, you used three input arguments, and found that the second argument was subtracted from the first, resulting in an answer of

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

>>>

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, you used one input argument and found the answer was 0, because MATLAB only found one argument to the function and used the

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

>>>

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, you find that MATLAB raises an error because there were more input arguments passed than were defined in the

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

There are four key takeaways from this example with MATLAB

1. There is only one kind of argument in a function definition
2. Ý nghĩa của một đối số trong mã được xác định bởi vị trí của nó trong định nghĩa hàm
3. The maximum number of arguments that can be passed to a function is determined by the number of arguments specified in the function definition
4. Any number of arguments up to the maximum can be passed by the caller

In Python, there are two kinds of arguments you can specify when defining a function. These are required and optional arguments. The key difference between these is that required arguments must be passed when a function is called, while optional are given a default value in the function definition

You can see the differences between these two styles in the next example

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, you are defining a function called

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

The third argument,

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In the body of the function, you are testing the value of

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In [2]: import antigravity

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

In addition to the two types of arguments you can use when defining a function, there are two kinds of arguments you can specify when calling a function. These are called positional and arguments. You can see the difference between these in the following example. First, try passing only two arguments to the function

>>>

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, you passed only two arguments to

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Since only the two required arguments were passed,

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

>>>

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In this code, you passed three arguments to

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In these examples, you saw that it is possible in Python to define default values for arguments to a function. This means when you call the function, any arguments with default values are optional and do not have to be passed. If no value is passed for any default arguments, the default value will be used. However, you must pass a value for every argument without a default value. Otherwise, Python will raise an error

>>>

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, you have only passed one of the two required arguments to

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

In these last three example, you have used positional arguments, so which parameter is assigned to the variables in the function depends on the order they are passed. There is another method to pass arguments to functions in Python, called keyword arguments. To use keyword arguments, you specify the name of the argument in the function call

>>>

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, you have used keyword arguments for all three arguments to

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

Another benefit of keyword arguments is that they can be specified in any order

>>>

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, you have specified the three arguments for

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

You can also mix positional and keyword arguments together in the same function call. If positional and keyword arguments are mixed together, the positional arguments must be specified first, before any keyword arguments

>>>

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, you have specified the values for

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

Finally, there is one last benefit of using keyword arguments and default values. Spyder, and other IDEs, provide introspection of function definitions. This will tell you the names of all of the defined function arguments, which ones have default arguments, and the value of the default arguments. This can save you time and make your code easier and faster to read

There Are No

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

14/

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

15 Blocks in Python

In MATLAB, you can use

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, you start by defining

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

This syntax is an interesting comparison of MATLAB vs Python because Python does not have a similar syntax. Thay vào đó, bạn nên sử dụng khối

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, you start by defining

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [2]: import antigravity

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

Namespaces Are One Honking Great Idea in Python

In MATLAB, all functions are found in a single scope. MATLAB has a defined search order for finding functions within the current scope. If you define your own function for something that MATLAB already includes, you may get unexpected behavior

As you saw in the Zen of Python, namespaces are one honking great idea. Namespaces are a way to provide different scopes for names of functions, classes, and variables. This means you have to tell Python which library has the function you want to use. Đây là một điều tốt, đặc biệt trong trường hợp có nhiều thư viện cung cấp cùng một chức năng

Chẳng hạn, thư viện

In [2]: import antigravity

To tell Python where a function is located, you first have to

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

>>>

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, on input line 1 you imported the

In [2]: import antigravity

In [2]: import antigravity

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

In [2]: import antigravity

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

The

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

You can also tell Python what name it should use for a library. For instance, it is very common to see

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

>>>

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, input line 3 imports NumPy and tells Python to put the library into the

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

There are two main caveats to using namespaces where you should be careful

1. You should not name a variable with the same name as one of the functions built into Python. You can find a complete list of these functions in the Python documentation. The most common variable names that are also built-in functions and should not be used are

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   01,

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   02,

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   03,

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   04,

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   05,

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   06,

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   07,

   In [2]: import antigravity
   

   91,

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   09, and

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   10

2. You should not name a Python file [one with the extension

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   11] with the same name as a library that you have installed. In other words, you should not create a Python file called

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   12. This is because Python searches the current working directory first when it tries to import a library. If you have a file called

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   12, that file will be found before the built-in

   In [2]: import antigravity
   

   88 library and you will probably see an

   In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
      ...:         wdir='C:/Users/Eleanor/.spyder-py3']
   

   15

The Most Recent Unassigned Result Is Available as

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

16 in Python

The MATLAB console uses

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

>>>

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, you use

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In the Python console [including the IPython/Spyder console], the output from the most recent calculation is stored in

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

>>>

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In this code, you use

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In the IPython console, there is one additional feature enabled. You can append a number after the underscore to retrieve the result of any previous line. Try the following code

>>>

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this code on input line 3 you are using

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

Notice that the Spyder Variable explorer does not show this variable by default, whereas

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

Anonymous Functions Are Created With the

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

29 Keyword in Python

MATLAB uses the the at-symbol [

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

You can try out the differences of anonymous functions in MATLAB vs Python with this example

>>>

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this code, the first input line defines the anonymous function with one input parameter,

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

Anonymous functions are most often used when you need to pass one function into another function. In these cases, it is often not necessary to assign the function definition to a variable

>>>

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this code, the first input line executes

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

Python sử dụng từ khóa

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

>>>

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this code, input line 1 defines the

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [3]: var_1 = 10
In [4]: var_2 = 20
In [5]: var_3 = var_1 + var_2
In [6]: var_3
Out[6]: 30

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In Python, the official style guide called PEP 8 assigning

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

 1# -*- coding: utf-8 -*-
 2"""
 3Spyder Editor
 4
 5This is a temporary script file.
 6"""

However,

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

>>>

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this code, input line 3 imports the

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

You can see that the result on output line 4 has two values,

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

You can read more about

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

Class Definitions Start With

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

66 in Python

MATLAB has two ways to define a class. With the first way, you can put all of the class definition in a single file with the name of the class as the filename. Then within the file, you can use the

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

With the second way, you can create a folder that starts with

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

Python only has one way to define a class, using the

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this code, the first line defines the name of the class. It starts with the

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

The second line in this code is a comment to note that the rest of the class definition would follow the

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

As in all object-oriented code, Python classes can inherit from superclasses. The superclass of a given class can be given as a parameter in the class definition, as shown below

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this code, the only change is that the name of the superclass is listed inside round brackets before the colon

There Are No Private Properties or Methods in Python

MATLAB allows class properties and method to be set as one of four

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

• In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
     ...:         wdir='C:/Users/Eleanor/.spyder-py3']
  

  76. Access to the property or method is unrestricted

• In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
     ...:         wdir='C:/Users/Eleanor/.spyder-py3']
  

  77. Access to the property or method is only allowed in this class or subclasses

• In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
     ...:         wdir='C:/Users/Eleanor/.spyder-py3']
  

  78. Access to the property or method is only allowed in this class

• In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
     ...:         wdir='C:/Users/Eleanor/.spyder-py3']
  

  79 or

  In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
     ...:         wdir='C:/Users/Eleanor/.spyder-py3']
  

  80. Access to the property or method is only allowed in the listed class or classes

This allows you to specifically control the ways that a property or class method can be accessed

In Python, there is no way to set a class or instance attribute or method as protected or private. All classes and class instances can have their attributes and methods changed at runtime. Python’s convention is that attributes and methods that start with an underscore [

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

As you saw in the section about , the underscore is not visible by default in the Spyder Variable explorer. This is because Spyder and other tools respect the convention that underscore indicates something should be non-public. However, underscores can be shown in the Spyder Variable explorer if you click the gear icon in the top right of that pane and uncheck the Exclude private variables item. This will also show other non-public variables as well

Python uses several special methods that start with a double-underscore [

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

If you want more information about Python’s classes, you can read Object-Oriented Programming in Python vs Java. Even though that article is about Java, Java is similar to the MATLAB OOP paradigm in terms of the nature of attributes and methods

A Class Refers to Itself as

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

84 in Python

MATLAB uses the name

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

Python uses the name

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

There Is One String Type in Python

Trong MATLAB, các chuỗi ký tự được lưu trữ trong mảng chuỗi khi bạn sử dụng dấu nháy kép [

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In character arrays, each character in the string occupies one column in the array. For multidimensional character arrays, each row of the array must have the same number of characters, which is to say, the same number of columns. This is shown in the example below

>>>

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this example, line 1 shows an attempt to define a 2-row character array using single quotes. However, the number of characters in

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [2]: import antigravity

On line 4, you successfully create a character array, and on the third input line you are checking the size of the array. The output shows that there are 2 rows, as expected, and 6 columns, since the length of both

In [2]: import antigravity

In [2]: import antigravity

This is not the case for string arrays. In string arrays, each string occupies one column in the array and each row in a multidimensional array must have the same number of strings, although each string can have different length. This is shown in the example below

>>>

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In this code, line 1 shows an attempt to define a 2-row string array using double quotes. However, the number of strings on the first row [2] does not match the number of strings in the second row [1], so MATLAB raises an error

On line 5, you successfully create a string array. Lưu ý rằng mặc dù số lượng ký tự khác nhau giữa

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [2]: import antigravity

In Python, there is only one string literal type, called

In [2]: import antigravity

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

In [7]: runfile['C:/Users/Eleanor/.spyder-py3/temp.py',
   ...:         wdir='C:/Users/Eleanor/.spyder-py3']

There is one additional way to define strings in Python, using triple-single-quotes [

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

In [2]: import antigravity

Bạn có thể đọc thêm về cách xác định chuỗi trong và Dữ liệu chuỗi và ký tự trong Python

You can generate similar data structures to the string arrays and character arrays in MATLAB using NumPy in Python. NumPy has several data types, or dtypes, that are related to strings. In Python 3, the default string dtype for arrays is a fixed-width Unicode string

>>>

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]

Trong mã này, bạn đang nhập thư viện NumPy trên dòng đầu vào 1 và gán nó cho chữ viết tắt

 8var_4 = 10
 9var_5 = 20
10var_6 = var_4 + var_5

11# %% This is a code cell
12var_7 = 42
13var_8 = var_7 * 2
14
15# %% This is a second code cell
16print["This code will be executed in this cell"]