python dictionary match keys in two dictionaries when the keys are combinations of two strings

Question

I have two python dictionaries:

dictA = {('a','b') : 1,('a','c') : 3,('b','c') : 1}
dictB = {('b','a') : 4,('a','d') : 6,('b','c') : 2}

I want to compare the keys of dictA and dictB for common keys. I have tried

comm = set(dictA.keys()) & set(dictB.keys())

But, this will only return ('b','c').

But,in my case, first key in both the dictionaries are same i.e. dictA[('a','b')] is equivalent to dictB[('b','a')]. How to do this ??

Your first keys are no the same. `In [32]: ('a', 'b') == ('b', 'a') Out[32]: False` — Konstantin, May 08 '15 at 05:58
What is the expected result? Will there be duplicates in the keys? — thefourtheye, May 08 '15 at 06:09
The expected result is [('b', 'a'), ('b', 'c')] or [('a', 'b'), ('b', 'c')] — user1894087, May 08 '15 at 06:47
@user1894087 Although it needs to take some time, I have a good solution! — Burger King, May 08 '15 at 06:59
Your statement `dictA[('a','b')] is equivalent to dictB[('b','a')` is **false** for both the keys as for the values they return. The order of elements in a tuple is significant (unless the elements have the same value), and creates different keys. — Anthon, May 08 '15 at 09:54

Burger King · Answer 1 · 2015-05-08T06:56:48.060

1

I have a more compact method.

I think it's more readable and easy to understand. You can refer as below:

These are your vars:

dictA = {('a','b') : 1,('a','c') : 3,('b','c') : 1}
dictB = {('b','a') : 4,('a','d') : 6,('b','c') : 2}

According your requirement to solve this problem:

print [ a for a in dictA if set(a) in [ set(i) for i in dictB.keys()]]

So you can get answer you want.

[('b', 'c'), ('a', 'b')]

edited May 08 '15 at 06:56

answered May 08 '15 at 06:25

Burger King

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score 1 · Answer 2 · edited May 23 '17 at 12:14

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Another solution, albeit less elegant than what Tony has suggested:

setA = [ frozenset(i) for i in dictA.keys() ]
setB = [ frozenset(i) for i in dictB.keys() ]
result = set(setA) & set(setB)
print( [tuple(i) for i in result] )

It uses frozenset in order to construct two sets of sets. Here's the kind of output you're gonna get:

[('b', 'c'), ('b', 'a')]

edited May 23 '17 at 12:14

Community

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answered May 08 '15 at 07:53

Alex Boklin

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score 0 · Answer 3 · answered May 08 '15 at 05:57

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That ('b','c') is returned is the correct answer. The tuple ('a', 'b') is not the same as the tuple ('b', 'a').

answered May 08 '15 at 05:57

Anthon

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python dictionary match keys in two dictionaries when the keys are combinations of two strings

3 Answers3