How to swap values in dictionary and find all possible outcomes?

Question

I have the following dictionary:

d = {
     'A': 50, 
     'B': 30, 
     'C': 20
      }

Is it possible to find and print all iterations of this dictionary based only on swapping the values?

E.g.

# First iteration
d = {'A': 50, 'B': 30, 'C': 20}

# Second iteration
d = {'A': 50, 'B': 20, 'C': 30}

# Third iteration
d = {'A': 30, 'B': 50, 'C': 20}

...

The values are unique and the order of swapping the values does not matter as long as all possible iterations are found.

@AzatIbrakov - All values are unique, I forgot to include that. — Joseph, Feb 01 '19 at 12:25
this doesn't help, can you list all possible "swappings" for case with at least 2 elements? — Azat Ibrakov, Feb 01 '19 at 12:27

Azat Ibrakov · Accepted Answer · 2019-02-01T12:55:09.123

We can obtain possible permutations using itertools library from stdlib

>>> from itertools import permutations
>>> d = {
     'A': 50, 
     'B': 30, 
     'C': 20
      }
>>> [dict(zip(d.keys(), values)) for values in permutations(d.values())]
[{'A': 50, 'B': 30, 'C': 20},
 {'A': 20, 'B': 30, 'C': 50},
 {'A': 30, 'B': 50, 'C': 20},
 {'A': 20, 'B': 50, 'C': 30},
 {'A': 30, 'B': 20, 'C': 50},
 {'A': 50, 'B': 20, 'C': 30}]

score 1 · Answer 2 · answered Feb 01 '19 at 12:27

Use itertools.permutations:

from itertools import permutations

d = {
     'A': 50, 
     'B': 30, 
     'C': 20
      }

vals = d.values()    
for x in permutations(vals, len(vals)):
    x = iter(x)
    print({k: next(x) for k in d})

# {'A': 50, 'B': 30, 'C': 20}
# {'A': 50, 'B': 20, 'C': 30}                                  
# {'A': 30, 'B': 50, 'C': 20}                                 
# {'A': 30, 'B': 20, 'C': 50}                                
# {'A': 20, 'B': 50, 'C': 30}                               
# {'A': 20, 'B': 30, 'C': 50}

OmG · Answer 3 · 2019-02-01T12:36:30.937

1

You can using permutation in itertools:

import itertools
[dict(zip(d.keys(), l)) for l in itertools.permutations(d.values())]

edited Feb 01 '19 at 12:36

answered Feb 01 '19 at 12:28

OmG

18,337
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score 1 · Answer 4 · answered Feb 01 '19 at 12:30

I don't know of any direct way to do this but you can make a permutation of the keys themselves (i.e "abc", "acb", "bac", "bca" etc') and use that to get the permutated values to your set.

for example with the permutated key set 'bca': key "a" gets the content of original dictionary "b". key "b" gets the content of original dictionary "c". key "c" gets the content of original dictionary "a".

and I'd get the permutated keyset from this question: Finding all possible permutations of a given string in python

score 1 · Answer 5 · answered Feb 01 '19 at 12:39

1

if you make a set with the keys and values you can use the itertools module, the combinations() function. From the result you eliminate the pairs with only keys.

here are details: https://docs.python.org/2/library/itertools.html#itertools.combinations

answered Feb 01 '19 at 12:39

Petronella

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How to swap values in dictionary and find all possible outcomes?

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