or — Expert Examples

Logical OR operator; returns True if at least one operand is true

EasyIntermediateAdvancedExpert

or bytecode: jump-if-true

How 'or' compiles differently from 'and'.

python
import dis

def or_expr(a, b):
    return a or b

def or_chain(a, b, c):
    return a or b or c

def mixed(a, b, c):
    return a and b or c

print("a or b:")
dis.dis(or_expr)
print("\na or b or c:")
dis.dis(or_chain)
print("\na and b or c:")
dis.dis(mixed)

# 'or' uses POP_JUMP_IF_TRUE (opposite of 'and')
# If left is truthy, keep it and skip right
# 'and' uses POP_JUMP_IF_FALSE
# If left is falsy, keep it and skip right

'or' compiles to POP_JUMP_IF_TRUE (skip right if left is truthy), while 'and' uses POP_JUMP_IF_FALSE (skip right if left is falsy). Mixed expressions chain these jumps together.

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