Understanding Python Syntax

Executing Python Syntax

In Python, syntax can be executed directly via the command line interface, making it especially accessible for beginners:

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

Alternatively, you can create a Python script using the .py extension and run it via the command line:

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

Python Indentation

Indentation in Python is not just for visual organization; it is a syntactical requirement. Unlike other programming languages where indentation is optional, Python uses indentation to define code blocks.

Correct example:

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

Incorrect example (causes syntax error):

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

The number of spaces used is flexible (commonly four), but consistency within the same block is essential to avoid errors.

if 5 > 2:
    print("Correct indentation")
if 5 > 2:
        print("Also valid, if consistent")

Incorrect example (mixed indentation):

if 5 > 2:
    print("First line")
        print("Second line")

Python Variables

Variables in Python are created upon assignment. There is no need to declare a variable type beforehand.

x = 5
y = "Hello, World!"

Python automatically recognizes the data type based on the assigned value. You’ll explore this further in the Python Variables chapter.

Writing Comments in Python

Comments in Python start with the # symbol. Everything after this symbol on the same line is treated as a comment and ignored during execution.

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

Comments are essential for making your code understandable to others and yourself.