Python built-in Method - hash()

The hash() method in Python is a built-in function that returns the hash value of an object. The hash value is a unique integer that is generated for each object by the Python interpreter.

The hash value of an object is based on its contents and is used by Python's built-in data structures, such as dictionaries and sets, to determine the object's position in memory.

The syntax for hash() is as follows:

hash(object)

Here, object is the object whose hash value is to be returned.

For example:

x = 10
y = "Hello, world!"
z = [1, 2, 3]

hash_x = hash(x)
hash_y = hash(y)
hash_z = hash(tuple(z))

print(hash_x)  # Output: 10
print(hash_y)  # Output: -7840116311032624766
print(hash_z)  # Output: 529344067295497451

In the example above, we define three objects: an integer x, a string y, and a list z. We use the hash() function to get the hash value of each object.

The hash value of the integer x is simply its value (10). The hash value of the string y and the list z are generated using the contents of the objects. Since the contents of a string or a list can change, their hash values can change as well.

Note that not all objects can be hashed in Python. Only immutable objects, such as numbers, strings, and tuples, can be hashed. Mutable objects, such as lists and dictionaries, cannot be hashed.

The hash() function is used internally by Python to implement many of its built-in data structures and algorithms. It can also be used in your own code to generate unique identifiers or to implement custom hash functions for your own objects.