Is hash() built-in in Python?

Is the hash function hash() built-in in Python? Let me introduce you to the relevant knowledge of hash functions:

hash(object)

If object is a hashable object, hash( ) function will return its hash value; if the object does not belong to a hashable object, the hash() function will throw an exception. The hash value is an integer.

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hash('orca_j35') #> 3721949548176702466
hash([1,2]) #> TypeError: unhashable type: 'list

When searching for a dictionary, hash values ​​are used to quickly compare dictionary keys. Objects with the same hash value are treated as the same key by the dictionary.

x = (1,2)y = (1,2)
# x和y是具备不同id的对象
x is y #> False
z = {x:"orca"}
# 只要哈希值相同，便可互换使用
z[y] #> 'orca'

Equal (==) values ​​have the same hash value. Even if two equal values ​​belong to different types, their hash values ​​are the same, such as 1 and 1.0:

1 == 1.0 #> True
hash(1),hash(1.0) #> (1, 1)

tips: Two equal (==) objects must have the same hash value, but returning them does not necessarily hold true.

Note:

For objects with custom __hash__() methods, the hash() function will truncate __hash__ according to the bit width of the host machine. () The return value.

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