CodingPhiles
➕ Operators & Expressions
Module 3 · Topic 3

Logical Operators

Combine conditions with and, or, not — and understand short-circuit evaluation for writing efficient code.

Theory

Logical Operators:

| Operator | Description | Example |
|----------|-------------|--------|
| and | True if BOTH are True | True and False → False |
| or | True if EITHER is True | True or False → True |
| not | Inverts the boolean | not True → False |

Short-Circuit Evaluation:
Python stops evaluating as soon as the result is determined:

  • and: If first operand is False, second is NOT evaluated
  • or: If first operand is True, second is NOT evaluated

Return Values (NOT just True/False!):

  • and returns the first falsy value, or the last value if all truthy
  • or returns the first truthy value, or the last value if all falsy

Examples:

  • "hello" and "world" → "world" (both truthy, returns last)
  • "" and "world" → "" (first is falsy, returns it)
  • "" or "default" → "default" (first falsy, returns second)
  • "hello" or "default" → "hello" (first truthy, returns it)

This is commonly used for default values: name = user_input or "Anonymous"

Syntax
x and y    # True if both True
x or y     # True if either True
not x      # Inverts boolean

# Short-circuit for defaults
value = user_input or "default"

# Short-circuit for safe access
result = obj and obj.method()