2.10. builtin - Mutable/ImmutableΒΆ

  • Mutable: An object that can be changed after it is created

    • list, set, dict

a = [1,2,3]
id(a)
>>> 63674848
a.append(4)
id(a)
>>> 63674848 # note that the ID stays the same, however the content of the list changed

  • Immutable: An object that cannot be changed after it is created

    • bool, int, float, str, tuple, frozenset

# same ID every time you call id on a bool, int, float, str
id(123)
>>> 1794170960
a = (1,2,3)
id(a)
>>> 69202848 # now note once you change the tuple size the ID rolls
a += (4,)
id(a)
>>> 65455520 # new id