Keywords

Keywords in Python:

1. Definition:

Keywords are reserved words in Python that have special meanings and are part of the language syntax. These words cannot be used as identifiers (variable names, function names, etc.) because they are reserved for specific purposes within the language.

2. Examples:

Here are some examples of keywords in Python:

• if: Used for conditional statements.
• else: Used for an alternative condition in conjunction with if.
• for: Used for looping over an iterable.
• while: Used for looping while a condition is true.
• def: Used for defining functions.
• return: Used for returning a value from a function.
• import: Used for importing modules.
• from: Used with import to import specific items from a module.
• class: Used for defining classes.
• try: Used for exception handling.
• except: Used for catching exceptions.
• finally: Used for executing code irrespective of whether an exception occurred or not.
• and, or, not: Used for logical operations.

3. Usage:

Keywords in Python have specific syntactical meanings and are integral to writing Python code. They cannot be used as variable names or identifiers.

Example:

# Using keywords in Python
if True:
    print("This is an if statement")
for i in range(5):
    print(i)
def greet(name):
    print("Hello, " + name)
return_value = greet("Alice")
import math
print(math.sqrt(25))

In this example:

• if, for, def, return, import, and print are all keywords used in Python code.
• They each serve a specific purpose within the code structure.

4. Differences:

1. Keywords vs. Identifiers:
   • Keywords are reserved words with predefined meanings in Python and cannot be used as identifiers.
   • Identifiers are user-defined names given to variables, functions, classes, etc., and should not conflict with keywords.
2. Keywords vs. Built-in Functions:
   • Keywords are part of the Python language syntax and have special meanings.
   • Built-in functions are pre-defined functions provided by Python for common tasks, like print(), len(), etc.
3. Keywords vs. Operators:
   • Keywords define control flow and structure in Python, like if, else, for, etc.
   • Operators perform operations on operands, like arithmetic operators (+, -, *, /), logical operators (and, or, not), etc.

Summary:

Understanding keywords in Python is essential for writing correct and meaningful code. They play a crucial role in defining the structure, control flow, and behavior of Python programs. It's important not to use keywords as identifiers to avoid syntax errors.

Keywords are likely to be covered in the Python PCEP exam as they are fundamental to the language syntax and are necessary for writing Python code effectively.