Mapping over values in a python dictionary

Question

Given a dictionary { k1: v1, k2: v2 ... } I want to get { k1: f(v1), k2: f(v2) ... } provided I pass a function f.

Is there an

Answer 1

You can do this in-place, rather than create a new dict, which may be preferable for large dictionaries (if you do not need a copy).

def mutate_dict(f,d):
    for k, v in d.iteritems():
        d[k] = f(v)

my_dictionary = {'a':1, 'b':2}
mutate_dict(lambda x: x+1, my_dictionary)

results in my_dictionary containing:

{'a': 2, 'b': 3}