Mapping types – dictionaries

Of all the built-in Python data types, the dictionary is easily the most interesting one. It's the only standard mapping type, and it is the backbone of every Python object.

A dictionary maps keys to values. Keys need to be hashable objects, while values can be of any arbitrary type. Dictionaries are mutable objects. There are quite a few different ways to create a dictionary, so let me give you a simple example of how to create a dictionary equal to {'A': 1, 'Z': -1} in five different ways:

>>> a = dict(A=1, Z=-1)>>> b = {'A': 1, 'Z': -1}>>> c = dict(zip(['A', 'Z'], [1, -1]))>>> d = dict([('A', 1), ('Z', -1)])>>> e = dict({'Z': -1, 'A': 1})>>> a == b == c == d == e  # are they all the same?True # They are indeed ...

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