Python

Chaining comparison operators in Python

Python Clean Code Tip:

Use chained comparison when you need to check whether some variable is between MIN and MAX values.

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from dataclasses import dataclass


@dataclass
class SurfBoard:
    width: float
    length: float


MINIMAL_LENGTH = 201.3
MAXIMAL_LENGTH = 278.5


# without chained comparison
def board_is_pwa_compliant(surf_board: SurfBoard):
    return surf_board.length > MINIMAL_LENGTH and surf_board.length < MAXIMAL_LENGTH


surf_board = SurfBoard(width=75.3, length=202.7)
print(board_is_pwa_compliant(surf_board))
# True


# with chained comparison
def board_is_pwa_compliant(surf_board: SurfBoard):
    return MINIMAL_LENGTH < surf_board.length < MAXIMAL_LENGTH


print(board_is_pwa_compliant(surf_board))
# True


# don't abuse it like this: a <= b < c > d