On Mon, 30 Apr 2007 12:50:58 -0500, Hamilton, William wrote:
>> On quick question, how can I order a dict by the 'values' (not keys)
>> before
>> looping? Is that possible?
>>
>
> The easiest way I can think of is to create a new dict that's reversed.
>
> reverseDict = {}
> for key in dict1:
> if dict1[key] not in reverseDict:
> reverseDict[dict1[key]]=[key]
> else:
> reverseDict[dict1[key]].append(key)
>
> This gives you a dictionary that has the old dict's values as keys, and
> the old dict's keys as lists of values. You can then sort the keys of
> this dict and do what you want with it. Of course, the values in dict1
> have to be valid dictionary keys for this to work. If they aren't, you
> may be able to get away with converting them to strings.
Oh man, maybe you need to re-think what you consider "easier".
for value in dict1.itervalues()
do_something_with(value)
If you need the keys as well:
for key, value in dict1.iteritems()
do_something_with(key, value)
If you need to process the values (say, sort them) first:
pairs = list(dict1.iteritems()) # or dict1.items()
pairs.sort()
for key, value in pairs:
do_something_with(key, value)
I'll leave sorting by value instead of key as an exercise.
--
Steven D'Aprano
--
http://mail.python.org/mailman/listinfo/python-list
