从多个键共享的字典中删除值

Question

I've got a dictionary built of title:substrings where the first three entries look like:

'1' : ['G', 'GA', 'GAA', 'GAAA', 'GAAAA', 'GAAAAA', 'GAAAAAG', 'GAAAAAGU', 'GAAAAAGUA', 'GAAAAAGUAU', 'GAAAAAGUAUG', 'GAAAAAGUAUGC', 'GAAAAAGUAUGCA', 'GAAAAAGUAUGCAA', 'GAAAAAGUAUGCAAG', 'GAAAAAGUAUGCAAGA', 'GAAAAAGUAUGCAAGAA', 'GAAAAAGUAUGCAAGAAC']

'2' : ['G', 'GA', 'GAG', 'GAGA', 'GAGAG', 'GAGAGA', 'GAGAGAG', 'GAGAGAGA', 'GAGAGAGAC', 'GAGAGAGACA', 'GAGAGAGACAU', 'GAGAGAGACAUA', 'GAGAGAGACAUAG', 'GAGAGAGACAUAGA', 'GAGAGAGACAUAGAG', 'GAGAGAGACAUAGAGG']

'3' : ['G', 'GU', 'GUC', 'GUCU', 'GUCUU', 'GUCUUU', 'GUCUUUG', 'GUCUUUGU', 'GUCUUUGU"', 'GUCUUUGU"G', 'GUCUUUGU"GU', 'GUCUUUGU"GUA', 'GUCUUUGU"GUAC', 'GUCUUUGU"GUACA', 'GUCUUUGU"GUACAU', 'GUCUUUGU"GUACAUC']

I found quite a few answers on how to convert them to lists and creating a for loop to check if items in 1 is in other and if so remove them, but I don't think that's feasible for me since this dictionary is generated and not handwritten by me. Because of that I don't really understand how I should be approaching this problem.

Answer 1

You could build an index where each value lists the keys it is in. If that list is greater than 1, remove that value.

mydict = {
'1' : ['G', 'GA', 'GAA', 'GAAA', 'GAAAA', 'GAAAAA', 'GAAAAAG', 'GAAAAAGU', 'GAAAAAGUA', 'GAAAAAGUAU', 'GAAAAAGUAUG', 'GAAAAAGUAUGC', 'GAAAAAGUAUGCA', 'GAAAAAGUAUGCAA', 'GAAAAAGUAUGCAAG', 'GAAAAAGUAUGCAAGA', 'GAAAAAGUAUGCAAGAA', 'GAAAAAGUAUGCAAGAAC'],

'2' : ['G', 'GA', 'GAG', 'GAGA', 'GAGAG', 'GAGAGA', 'GAGAGAG', 'GAGAGAGA', 'GAGAGAGAC', 'GAGAGAGACA', 'GAGAGAGACAU', 'GAGAGAGACAUA', 'GAGAGAGACAUAG', 'GAGAGAGACAUAGA', 'GAGAGAGACAUAGAG', 'GAGAGAGACAUAGAGG'],

'3' : ['G', 'GU', 'GUC', 'GUCU', 'GUCUU', 'GUCUUU', 'GUCUUUG', 'GUCUUUGU', 'GUCUUUGU"', 'GUCUUUGU"G', 'GUCUUUGU"GU', 'GUCUUUGU"GUA', 'GUCUUUGU"GUAC', 'GUCUUUGU"GUACA', 'GUCUUUGU"GUACAU', 'GUCUUUGU"GUACAUC']
}

# build a dict of values and the keys that hold them
tmpdict = defaultdict(list)
for key, values in mydict.items():
    for value in values:
        tmpdict[value].append(key)

# now remove offenders from the original list
for value, inkeys in tmpdict.items():
    if len(inkeys) > 1:
        for key in inkeys:
            mydict[key].remove(value)

print mydict

Answer 2

Removing arbitrary items from lists leads to poor performance when you need to scale. It's usually better to make new lists from the old and leave out the items you wanted to remove.

Here, the items you wish to remove are values that have a count greater than 1

>>> mydict = {
... '1' : ['G', 'GA', 'GAA', 'GAAA', 'GAAAA', 'GAAAAA', 'GAAAAAG', 'GAAAAAGU', 'GAAAAAGUA', 'GAAAAAGUAU', 'GAAAAAGUAUG', 'GAAAAAGUAUGC', 'GAAAAAGUAUGCA', 'GAAAAAGUAUGCAA', 'GAAAAAGUAUGCAAG', 'GAAAAAGUAUGCAAGA', 'GAAAAAGUAUGCAAGAA', 'GAAAAAGUAUGCAAGAAC'],
... '2' : ['G', 'GA', 'GAG', 'GAGA', 'GAGAG', 'GAGAGA', 'GAGAGAG', 'GAGAGAGA', 'GAGAGAGAC', 'GAGAGAGACA', 'GAGAGAGACAU', 'GAGAGAGACAUA', 'GAGAGAGACAUAG', 'GAGAGAGACAUAGA', 'GAGAGAGACAUAGAG', 'GAGAGAGACAUAGAGG'],
... '3' : ['G', 'GU', 'GUC', 'GUCU', 'GUCUU', 'GUCUUU', 'GUCUUUG', 'GUCUUUGU', 'GUCUUUGU"', 'GUCUUUGU"G', 'GUCUUUGU"GU', 'GUCUUUGU"GUA', 'GUCUUUGU"GUAC', 'GUCUUUGU"GUACA', 'GUCUUUGU"GUACAU', 'GUCUUUGU"GUACAUC']
... }
>>> from collections import Counter
>>> from itertools import chain
>>> c = Counter(chain.from_iterable(mydict.values()))
>>> {k: [x for x in v if c[x] == 1] for k, v in mydict.items()}
{'1': ['GAA', 'GAAA', 'GAAAA', 'GAAAAA', 'GAAAAAG', 'GAAAAAGU', 'GAAAAAGUA', 'GAAAAAGUAU', 'GAAAAAGUAUG', 'GAAAAAGUAUGC', 'GAAAAAGUAUGCA', 'GAAAAAGUAUGCAA', 'GAAAAAGUAUGCAAG', 'GAAAAAGUAUGCAAGA', 'GAAAAAGUAUGCAAGAA', 'GAAAAAGUAUGCAAGAAC'],
 '3': ['GU', 'GUC', 'GUCU', 'GUCUU', 'GUCUUU', 'GUCUUUG', 'GUCUUUGU', 'GUCUUUGU"', 'GUCUUUGU"G', 'GUCUUUGU"GU', 'GUCUUUGU"GUA', 'GUCUUUGU"GUAC', 'GUCUUUGU"GUACA', 'GUCUUUGU"GUACAU', 'GUCUUUGU"GUACAUC'], 
 '2': ['GAG', 'GAGA', 'GAGAG', 'GAGAGA', 'GAGAGAG', 'GAGAGAGA', 'GAGAGAGAC', 'GAGAGAGACA', 'GAGAGAGACAU', 'GAGAGAGACAUA', 'GAGAGAGACAUAG', 'GAGAGAGACAUAGA', 'GAGAGAGACAUAGAG', 'GAGAGAGACAUAGAGG']}