algorithm - Combinations from dictionary with list values using Python

Question

I have the following incoming value:

variants = {
  "debug" : ["on", "off"],
  "locale" : ["de_DE", "en_US", "fr_FR"],
  ...
}

I want to process them so I get the following result:

combinations = [
  [{"debug":"on"},{"locale":"de_DE"}],
  [{"debug":"on"},{"locale":"en_US"}],
  [{"debug":"on"},{"locale":"fr_FR"}],
  [{"debug":"off"},{"locale":"de_DE"}],
  [{"debug":"off"},{"locale":"en_US"}],
  [{"debug":"off"},{"locale":"fr_FR"}]
]

This should work with arbitrary length of keys in the dictionary. Played with itertools in Python, but did not found anything matching these requirements.

Answer 1

import itertools as it

varNames = sorted(variants)
combinations = [dict(zip(varNames, prod)) for prod in it.product(*(variants[varName] for varName in varNames))]

Hm, this returns:

[{'debug': 'on', 'locale': 'de_DE'},
 {'debug': 'on', 'locale': 'en_US'},
 {'debug': 'on', 'locale': 'fr_FR'},
 {'debug': 'off', 'locale': 'de_DE'},
 {'debug': 'off', 'locale': 'en_US'},
 {'debug': 'off', 'locale': 'fr_FR'}]

which is probably not exactly, what you want. Let me adapt it...

combinations = [ [ {varName: val} for varName, val in zip(varNames, prod) ] for prod in it.product(*(variants[varName] for varName in varNames))]

returns now:

[[{'debug': 'on'}, {'locale': 'de_DE'}],
 [{'debug': 'on'}, {'locale': 'en_US'}],
 [{'debug': 'on'}, {'locale': 'fr_FR'}],
 [{'debug': 'off'}, {'locale': 'de_DE'}],
 [{'debug': 'off'}, {'locale': 'en_US'}],
 [{'debug': 'off'}, {'locale': 'fr_FR'}]]

Voilà ;-)