How to swap keys for values in a dictionary [duplicate]

Question

I receive a dictionary as input, and would like to to return a dictionary whose keys will be the input's values and whose value will be the corresponding input keys. Values are unique.

For example, say my input is:

a = dict() a['one']=1 a['two']=2 

I would like my output to be:

{1: 'one', 2: 'two'} 

To clarify I would like my result to be the equivalent of the following:

res = dict() res[1] = 'one' res[2] = 'two' 

Any neat Pythonic way to achieve this?

Answer 1

Python 2:

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

Python 3 (thanks to @erik):

res = dict((v,k) for k,v in a.items())