Chained Comparison

In Python, using chained comparison operators is a way to simplify multiple comparison and thus more efficient.

Comparisons

#

# comparison operators
comparisons = [ 
    '<', '>', '<=', '>=', '==', '!=',
    'is', 'is not', 'in', 'not in' 
    ]

Chained_Comparison

#

I didn’t know that Python does support chained comparison until today.

I used to do this in the past:

def main():
    x, y, z = 0, 1, 2
    if x < y and y < z:
        print(True)
    else:
        print(False)

By using chained comparison, I can simply do this way:

def main():
    x, y, z = 0, 1, 2

    if x < y < z:
        print(True)
    else:
        print(False)

The difference between the two methods above is, the y is evaluated only once (in method 2).