To comment multiple lines in python

Shortcut to Comment Out Multiple Lines in Python

We often need to comment out blocks of code in Python while testing or debugging the code. When a block is turned into a Python comment, it doesn’t contribute to the output of the program and helps to determine which function or block is generating an error in the program. This article discusses shortcuts to comment out multiple lines of code at once in different Python IDEs such as Spyder, IDLE, Jupyter Notebook, and PyCharm. Let’s see examples to comment out multiple lines of code in Python in each IDE one by one.

Shortcut to Comment Out Multiple Lines in Spyder IDE

In spyder python IDE, we can comment out a single line of code by selecting the line and then using the key combination ctrl+1 . This will turn the selected single line into a comment as shown below. The function given in the example adds a number and its square to a Python dictionary key-value pair.

print("This line will be commented out.") def add_square_to_dict(x,mydict): a=x*x mydict[str(x)]=a return mydict 

If we select the print statement above the function definition and press ctrl+1 , the code will look as follows.

#print("This line will be commented out.") def add_square_to_dict(x,mydict): a=x*x mydict[str(x)]=a return mydict 

The shortcut to comment out multiple lines of code in Spyder IDE is as follows.

We first select all the lines that we need to comment out using the cursor. Then, we press the key combination ctrl+4 . After this, the selected lines are converted into a Python comments. For example, consider the following code.

 class MyNumber(): """This is the docstring of this class. It describes what this class does and all its attributes.""" def __init__(self, value): self.value=value def increment(self): """This is the docstring for this method. It describes what the method does, what are its calling conventions and what are its side effects""" self.value=self.value+1 return self.value print (MyNumber.increment.__doc__)

If select the above code snippet and press ctrl+4, the code will be commented as shown in the following code.

# ============================================================================= # # class MyNumber(): # """This is the docstring of this class. # # It describes what this class does and all its attributes.""" # def __init__(self, value): # self.value=value # def increment(self): # """This is the docstring for this method. # # It describes what the method does, what are its calling conventions and # what are its side effects""" # self.value=self.value+1 # return self.value # print (MyNumber.increment.__doc__) # =============================================================================

How to Uncomment Code in Spyder IDE?

• We can use ctrl+1 to uncomment the lines of code after selecting them when they are commented out.
• In some versions of Spyder ctrl+5 can be used to uncomment the lines of code.

Shortcut to Comment Out Multiple Lines in IDLE

To comment out a block of code in IDLE, we have to first select the code that we want to comment out. Then, we need to press the key combination ctrl+D . This will comment out the selected lines of code. For example, consider that we write the following code in the IDLE.

 class MyNumber(): """This is the docstring of this class. It describes what this class does and all its attributes.""" def __init__(self, value): self.value=value def increment(self): """This is the docstring for this method. It describes what the method does, what are its calling conventions and what are its side effects""" self.value=self.value+1 return self.value print (MyNumber.increment.__doc__)

Once we select the code and press ctrl+D , the lines of code will be commented out as shown in the following image.

Uncomment Code in IDLE

To uncomment the lines of code in IDLE, we just have to select the lines and then press ctrl+shift+D . This will uncomment the selected lines as shown below.

Shortcut to Comment Out Multiple Lines in Jupyter Notebook

We can use ctrl+/ to comment out the selected lines of Python code in Jupyter Notebook. This turns selected lines of code into comments. For example, let us paste the following code into a Jupyter Notebook cell.

After pressing the keys ctrl+/ , the code will be commented out as shown below.

Uncomment Code in Jupyter Notebook

To uncomment the selected lines in Jupyter Notebook, we just have to again press ctrl+/ . This will uncomment the code from the Jupyter Notebook as shown below.

Comment Out Multiple Lines in PyCharm

If we have to comment out multiple lines of code in Pycharm, we can select the lines to be commented out and then press ctrl+/ . After this, the lines will be commented out from the code. To understand this, consider that we have written the following code in PyCharm.

When we select the code and press ctrl+/ , the code will be commented out as shown in the following image.

Uncomment Code in PyCharm

To uncomment the code in PyCharm, we just have to select the lines and then again press ctrl+/ . After this, the comments will be turned into code as shown below.

Conclusion

In this article, we have seen shortcuts to comment out multiple lines at once in Python in different IDEs like Spyder, IDLE, Jupyter Notebook, and PyCharm.

To learn more about Python programming, you can read this article on string manipulation in Python. You might also like this article on Python simplehttpserver.

I hope you enjoyed reading this article. Stay tuned for more informative articles.

Источник

Python Multiline Comment – How to Comment Out Multiple Lines in Python

Kolade Chris

Commenting is an integral part of every programming language. With comments, you get a better understanding of your own code, make it more readable, and can help team members understand how it works.

Comments are ignored by compilers and interpreters, so they don’t run.

Apart from making your code more readable, comments can also help while you’re debugging – if you have two lines of code, you can comment out one to prevent it from running.

Just like other programming languages, Python supports comments.

The problem is that Python doesn’t have a built-in mechanism for multi-line comments.

So in this article, I won’t just show you how to make single-line comments in Python – I’ll also show you the workaround for making multi-line comments.

How to Make Single Line Comments in Python

To make single-line comments in Python, prepend each line with a hash ( # ).

# print("Hello world") print("Hello campers") 

As you can see, the commented line wasn’t printed in the output.

How to Make Multi-line Comments in Python

Unlike other programming languages such as JavaScript, Java, and C++ which use /*. */ for multi-line comments, there’s no built-in mechanism for multi-line comments in Python.

To comment out multiple lines in Python, you can prepend each line with a hash ( # ).

# print("Hello world") # print("Hello universe") # print("Hello everyone") print("Hello campers") 

With this approach, you’re technically making multiple single-line comments.

The real workaround for making multi-line comments in Python is by using docstrings.

If you use a docstring to comment out multiple line of code in Python, that block of code will be ignored, and only the lines outside the docstring will run.

""" This is a multi-line comment with docstrings print("Hello world") print("Hello universe") print("Hello everyone") """ print("Hello campers") 

NB: One thing to note is that while using doctsrings for commenting, indentation still matters. If you use 4 spaces (or a tab) for indentation, you will get an indentation error.

For example, this will work:

def addNumbers(num1, num2, num3): """ A function that returns the sum of 3 numbers """ return num1 + num2 + num3 print(addNumbers(2, 3, 4)) # Output: 9 

def addNumbers(num1, num2, num3): """ A function that returns the sum of 3 numbers """ return num1 + num2 + num3 print(addNumbers(2, 3, 4)) 

So your IDE will throw the error » IndentationError: expected an indented block «.

Conclusion

Since there’s no built-in support for multi-line comments in Python, this article demonstrates how you can use docstrings as a workaround.

Still, you should generally stick to using regular Python comments using a hash ( # ), even if you have to use it for multiple lines. This is because docstrings are meant for documentation, and not for commenting out code.

If you found this article helpful, consider sharing it with your friends and family.

Источник

Python Multiline Comments Or How To Comment Multiple Lines

Python has several ways to comment multiple lines in Python. One option is to add # at the start of each line. PEP 8 and bigger part of the community prefers to comment out like:

# This is a comment # with multiple lines 

""" This is a comment with multiple lines """ 

Multiline comments in Python can start with »’ and end with »’ . Multiline comment is created simply by placing them inside triple-quoted strings: »’ / «»» and »’ / «»» .

Both examples have valid syntax in Python.

How to comment out multiple lines in Python

In Python there is a special symbol for comments which is # . Some languages like Java have native support for multiline comments.

Python multiline comment would look like to:

# This # is a # multi-line # comment 

This is the default comment for most popular Python IDEs like PyCharm, Sublime, VS code.

Python multiline comments and docstrings

Guido van Rossum (the Python creator, Python BDFL) tweeted once a «pro tip» for Python multiline comments:

According to this tip you can do comments in this way:

"""line1 line2 line3""" '''line1 line2 line3''' 

What is a docstring? The first statement in a class, method, function or module definition which is a string is called a docstring. Example:

def is_palindrome(word): """Check if word is a palindrome.""" str(word) == str(word)[::-1] 

Note 1: Even if a docstring contains only one line, triple quotes should be used because it’s easier to expand it in future.

Note 2: For one liners it is recommended the quotes to be on the same line as the comment.

Multiline docstrings example

Descriptive multiline docstrings help for understanding and maintaining the code. Here you can find an example for such:

def complex(real=0.0, imag=0.0): """Form a complex number. Keyword arguments: real -- the real part (default 0.0) imag -- the imaginary part (default 0.0) """ if imag == 0.0 and real == 0.0: return complex_zero . 

Many projects and organizations are using this kind of comments when they want to have good documentation.

The example image below multiline commend and docstring:

Shortcuts to comment multiple lines in Python and most popular IDEs

For commenting several lines in most popular IDEs you can use next shortcuts.

First you need to select the lines and then press:

• Pycharm — CTRL + / — comment / uncomment
• Eclipse — CTRL + / — comment / uncomment
• Sublime — CTRL + / — comment / uncomment
• Atom — CTRL + / — comment / uncomment
• IDLE — CTRL + ALT + 3 — comment, CTRL + ALT + 4 — uncomment
• Notepad++ — CTRL + Q — comment / uncomment
• vim — CTRL + Q / kbd>CTRL + V — comment / uncomment
• VS Code — CTRL + / — comment / uncomment

Note: If you like to add a multiline docstring than you can use different combination:

• Pycharm — Alt + Enter inside the function and select Insert documentation string stub
• VS Code — Alt + Shift + A — comment / uncomment

PyCharm comment multiple lines

Pycharm comment shortcut

The shortcut to comment multiple lines in Python and PyCharm are:

Pycharm comment out multiple lines

To comment several lines of code in the Pycharm follow next steps:

• Select the code lines
• Menu
• Code
• Comment with Line Comment
  • Windows or Linux: Ctrl + /
  • Mac OS: Command + /

  # time.sleep(50 / 1000) # 50 ms # time.sleep(5) # 5 secs # time.sleep(60) # 1 min 

  Pycharm uncomment multiple lines

  To uncomment commented lines in PyCharm you can do it by the same steps as commenting:

  • Select the code lines
  • Menu
  • Code
  • Comment with Line Comment
    • Windows or Linux: Ctrl + /
    • Mac OS: Command + /

    time.sleep(50 / 1000) # 50 ms time.sleep(5) # 5 secs time.sleep(60) # 1 min 

    Note: If you try to comment mixed lines code and comments then

    • the first press Ctrl + / will comment all lines (adding the second comment symbol # # in front of the commented lines)
    • the second one Ctrl + / will uncomment all lines (only the first comment sign)

    # time.sleep(50 / 1000) # 50 ms # time.sleep(5) # 5 secs time.sleep(60) # 1 min time.sleep(60 * 60) # 1 hour 

    # time.sleep(50 / 1000) # 50 ms # # time.sleep(5) # 5 secs # time.sleep(60) # 1 min # time.sleep(60 * 60) # 1 hour 

    Python remove all comments from a project with regex finders

    You can delete all Python comments from your Python project by(in Pycharm):

    * doc string with new lines inside 

    Источник