Question

I’m curious how the Python Ninjas around here would do the following, elegantly and pythonically:

I’ve got a data structure that’s a dict from unicode strings to dicts from unicode strings to unicode string lists. So:

>>> type(myDict)
<type 'dict'>
>>> type(myDict[u'myKey'])
<type 'dict'>
>>> type(myDict[u'myKey'][u'myKey2'])
<type 'list'>
>>> type(myDict[u'myKey'][u'myKey2'][0])
<type 'unicode'>

I want to go through and make every string in it lowercase, i.e. every key and every string in every list.

How would you do this?

Answer 1

Really simple way, though I’m not sure you’d call it Pythonic:

newDict = eval(repr(myDict).lower())

Saner way:

newDict = dict((k1.lower(),
                dict((k2.lower(),
                      [s.lower() for s in v2]) for k2, v2 in v1.iteritems()))
               for k1, v1 in myDict.iteritems())