Python - Keywords and Identifier

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Inception: This tutorial provides a comprehensive overview of Python keywords and identifiers, highlighting their significance and usage in Python programming.

Python is a high-level programming language that uses keywords and identifiers to identify various elements of the code. Keywords are reserved words that have a predefined meaning in the language, while identifiers are user-defined words that represent variables, functions, classes, or other objects. Understanding the difference between keywords and identifiers is essential for writing Python code correctly.

Keywords in Python

Keywords are special reserved words in Python that have a predefined meaning in the language. They are used to define the syntax and structure of the code. Keywords cannot be used as identifiers in Python. Here is a list of all the keywords in Python:

and       as        assert    break     class     
continue  def       del       elif      else      
except    False     finally   for       from      
global    if        import    in        is        
lambda    None      nonlocal  not       or        
pass      raise     return    True      try       
while     with      yield

Example:

# Example of using 'if' and 'else' keywords in Python:

x = 10
if x > 5:
  print("x is greater than 5")
else:
  print("x is less than or equal to 5")

In this example, 'if' and 'else' are keywords in Python that are used to control the flow of the code.

Let’s explore some common Python keywords!

  • if, else, elif: Used for conditional statements.
  • for, while: Used for loop constructs.
  • def: Used to define functions.
  • return: Used to return values from functions.
  • True, False: Boolean literals.
  • None: Represents null or absence of value.
  • and, or, not: Logical operators.
  • in, not in: Used to test membership in sequences.
  • is, is not: Used for identity testing.
  • import, from, as: Used for importing modules and symbols.

Identifiers in Python

Identifiers are user-defined words that represent variables, functions, classes, or other objects in Python. Identifiers must follow certain naming conventions in Python. They must start with a letter or an underscore and cannot start with a number. Identifiers can contain letters, numbers, and underscores. Identifiers are case-sensitive, which means that 'MyVar' and 'myvar' are two different identifiers.

Here are some rules for naming identifiers in Python!

  • Identifiers can contain letters (both uppercase and lowercase), digits, and underscores.
  • Identifiers cannot start with a digit.
  • Keywords cannot be used as identifiers.
  • Identifiers are case-sensitive.
  • It’s recommended to use descriptive names for identifiers to enhance code readability.

Example:

# Example of using identifiers in Python:

my_var = 10
print(my_var)

def my_function():
  print("Hello, World!")

my_function()

In this example, 'my_var' and 'my_function' are identifiers in Python that represent a variable and a function, respectively.

Conclusion

Understanding Python keywords and identifiers is essential for writing clean, readable, and error-free code. By familiarizing yourself with Python’s keywords and following the naming conventions for identifiers, you’ll be better equipped to express your logic effectively and efficiently in Python programs.

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