Python Syntax

 

Execute Python Syntax

As we learned in the previous page, Python syntax can be executed by writing directly in the Command Line:

>>> print("Hello, World!")
Hello, World!

On this page

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Execute Python SyntaxPython IndentationPython VariablesPython CommentsExercises

Or by creating a python file on the server, using the .py file extension, and running it in the Command Line:

C:\Users\Your Name>python myfile.py

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Python Indentation

Indentation refers to the spaces at the beginning of a code line.

Where in other programming languages the indentation in code is for readability only, the indentation in Python is very important.

Python uses indentation to indicate a block of code.

Example

if 5 > 2:
  print("Five is greater than two!")

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Python will give you an error if you skip the indentation:

Example

Syntax Error:

if 5 > 2:
print("Five is greater than two!")

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The number of spaces is up to you as a programmer, the most common use is four, but it has to be at least one.

Example

if 5 > 2:
 print("Five is greater than two!") 
if 5 > 2:
        print("Five is greater than two!") 

Try it Yourself »

You have to use the same number of spaces in the same block of code, otherwise Python will give you an error:

Example

Syntax Error:

if 5 > 2:
 print("Five is greater than two!")
        print("Five is greater than two!")

Try it Yourself »

Python Variables

In Python, variables are created when you assign a value to it:

Example

Variables in Python:

x = 5
y = "Hello, World!"

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Python has no command for declaring a variable.

You will learn more about variables in the Python Variables chapter.

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Comments

Python has commenting capability for the purpose of in-code documentation.

Comments start with a #, and Python will render the rest of the line as a comment:

Example

Comments in Python:

#This is a comment.
print("Hello, World!")

Try it Yourself »

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Test Yourself With Exercises

Exercise:

Insert the missing part of the code below to output "Hello World".

("Hello World")

Start the Exercise