CODEWITHSUNDEEP
pythonpython-3.x
zer0uno
zer0uno

Reputation: 8030

user-defined class: hash() and id() and doc

According to the doc:

Objects which are instances of user-defined classes are hashable by default; they all compare unequal (except with themselves), and their hash value is their id().

Now from console:

class ABC:
  def __init__(self):
    pass

a = ABC()
id(a)
140102888165648
hash(a)
8756430510353

Shoudln't a have the same hash and id value?

Upvotes: 2

Views: 112

Answers (1)

Bakuriu
Bakuriu

Reputation: 101919

According to the documentation for __hash__()

User-defined classes have __cmp__() and __hash__() methods by default; with them, all objects compare unequal (except with themselves) and x.__hash__() returns a result derived from id(x).

It seems like the glossary is either outdated or inaccurate.

The documentation for python3's __hash__ is slightly different:

User-defined classes have __eq__() and __hash__() methods by default; with them, all objects compare unequal (except with themselves) and x.__hash__() returns an appropriate value such that x == y implies both that x is y and hash(x) == hash(y).

So they even removed the fact that such value should depend on id.

Upvotes: 3

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