CODEWITHSUNDEEP
pythondictionary
baobobs
baobobs

Reputation: 703

Filtering items within Python dictionary values containing strings of tuples

I need to create a new dictionary from the following:

{'FOO': "('BAR','BAA'),('CAR','CAA')", 'FOOO': "('BAAR','BAAA'),('CAAR','CAAA')"}

I want to retrieve items within the strings of tuples in the dictionary values, and create a new dictionary using the original keys and the retrieved items as corresponding values. The retrieved items must be by placement (first item of every tuple). The completed dictionary should look like the following:

{'FOO': ('BAR','CAR'), 'FOOO': ('BAAR','CAAR')

This should be relatively easy, but I've been pulling my hair out trying to make this work.

Upvotes: 2

Views: 166

Answers (3)

abarnert
abarnert

Reputation: 365817

First, ast.literal_eval will turn each "('BAR','BAA'),('CAR','CAA')" into (('BAR', 'BAA'), ('CAR', 'CAA')).

Then you can just do [0] to get the first one. Is that all you were missing?

It's worth noting that, as a general rule, if you're using literal_eval, you're usually doing something wrong. For example, maybe instead of storing a string literal version of a tuple, you can store a JSON array, or a pickled or marshalled tuple.

Upvotes: 2

user2018323
user2018323

Reputation:

It might be not the best way to do it, but you can solve it with regular expressions.

import re

di={'FOO': "('BAR','BAA'),('CAR','CAA')",
      'FOOO': "('BAAR','BAAA'),('CAAR','CAAA')"}

ndi = {}
for k in di:
    ndi[k] = re.findall('\(\'(\w+)\'\,', di[k])

Upvotes: 1

nneonneo
nneonneo

Reputation: 179462

You can use ast.literal_eval to parse those strings. Then it's just a matter of pulling out the right elements.

d = {'FOO': "('BAR','BAA'),('CAR','CAA')", 'FOOO': "('BAAR','BAAA'),('CAAR','CAAA')"}
d2 = {k: zip(*ast.literal_eval(v))[0] for k,v in d.iteritems()}
# d2 is now {'FOO': ('BAR', 'CAR'), 'FOOO': ('BAAR', 'CAAR')}

Upvotes: 3

Related Questions