Reverse the one-to-one mapped dictionary

Question

Suppose there is a dictionary

a = {'a':122,'b':123,'d':333,'e':'233'}

Now I want to revert it as its a one-to-one dictionary so we can do that.

What I have tried:

In [67]: ivd=[(v,k) for (k,v) in a.items()]

In [68]: ivd
Out[68]: [(122, 'a'), (123, 'b'), ('233', 'e'), (333, 'd')]

Now may be some how We can convert this ivd into a dictionary. My questions are

1. How to change this ivd into a dictionary ?
2. Is there any more pythonic solution available to do this? which I think it should be there.

Answer 1

You can use dict constructor:

ivd = dict((v, k) for (k, v) in a.iteritems())

or dict comprehension in python 2.7 or later:

ivd = {v: k for (k, v) in a.items()}