164 – Chaining comparison operators

Python has plenty of comparison operators:

• <, <=, >, >=

• ==, !=

• in, not in

• is, is not

All of these comparison operators can be chained together. For example, writing floor <= value <= ceiling is the same as writing floor <= value and value <= ceiling.

Chaining comparison operators can improve code readability, but only if

• used in sequences of < / <= signs; or

• used in sequences of > / >= signs.

Mixing different comparison operators will lead to code that is hard to parse. For example, value in mylist == True looks like (value in mylist) == True, but it’s actually value in mylist and mylist == True, which will always be false if mylist is a list.

Further reading:

• Chaining comparison operators