hash

Calculate the hash of an object, the number dictionaries and sets use to look up keys.

Python 3.13
hash(object)

Parameters

objectAny: A hashable object.

Return value

An int; raises TypeError for an unhashable object.

Examples

Equal numbers, equal hash

Python 3.13
print(hash(42), hash(1.0), hash(True))
42 1 1

A list is not hashable

Python 3.13
try:
    hash([1, 2])
except TypeError as error:
    print(error)
unhashable type: 'list'

Details

Equal objects always have the same hash, so 1, 1.0 and True are the same dictionary key. The hash of strings changes between program runs, so do not save it to a file. Mutable collections, such as lists, dictionaries and sets, are not hashable.