Union of dict objects in Python

You can also use update method of dict like

a = {'a' : 0, 'b' : 1}
b = {'c' : 2}

a.update(b)
print a

This question provides an idiom. You use one of the dicts as keyword arguments to the dict() constructor:

dict(y, **x)

Duplicates are resolved in favor of the value in x; for example

dict({'a' : 'y[a]'}, **{'a', 'x[a]'}) == {'a' : 'x[a]'}