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
Have you noticed those double equals? Assignment is done with one equal, while to check whether an object is the same as another one (or five in one go, in this case), we use double equals. There...