Change The Value Of A Dictionary To Key Of A Dictionary In Python

I want to create a 'real' dictionary: a Dutch to English dictionary with the following words: def reversTranslation(dictionary): >>> dictionary= {'tension': ['spanning'],

Solution 1:

Here you go:

defreverseTranslation(d):
    returndict((v1,[k for k,v in d.iteritems() if v1 in v])
                for v1 inset(sum(d.values(),[])))

Solution 2:

If you are asking how to obtain that result, the most readable way is:

from collections import defaultdict

defreverse_dictionary(dictionary):
    result = defaultdict(list)
    for key, meanings in dictionary.iteritems():  #or just .items()for meaning in meanings:
            result[meaning].append(key)
    return result

Or you can first sum up the values and then iterate on the dictionary.

Solution 3:

d= {'tension': ['spanning'], 'voltage': ['spanning', 'voltage'],'extra':['voltage']}
val = set(reduce(list.__add__,d.values()))

dict={}
for x in val:
    tmp={x:[]}
    for k,v in d.items():
        if x in v:
           tmp[x].append(k)
    dict.update(tmp)

printdict

Note: collections are available only from python 2.4 and later