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pythonlistdictionarypython-itertools

product of two lists in python


How to combine 2 lists in such a way that each element in list 2 is combined with the elements in list 1 so that “a” combines with only one element in list 1 in each iteration then “b” combines with only two elements in the list 1 in each iteration.

list1= [1,2,3]

list2= [‘a’,‘b’,‘c’,‘d’,‘e’]

dict_list_2 = {‘a’ : 1 , ‘b’ : 2 , ‘c’ : 3 , ‘d’ : 4 , ‘e’ :5}

Expected Output: ('a',1) (a ,2 ) (a , 3) (b , 1 ,2) (b , 1 ,3) (b , 2 ,3) (b , 1 ,1) (b , 2 ,2) (b , 3 ,3) – 

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Solution

  • Assuming you want all combinations with replacement from list1:

    import itertools
    
    list1= [1,2,3]
    list2= list("abcde")
    dict_list_2 = {"a" : 1 , "b" : 2 , "c" : 3 , "d" : 4 , "e" :5}
    
    [(letter,) + product
     for letter in list2
     for product in itertools.product(list1, repeat=dict_list_2[letter])]
    
    # out:
    [('a', 1),
     ('a', 2),
     ('a', 3),
     ('b', 1, 1),
     ('b', 1, 2),
     ('b', 1, 3),
     ('b', 2, 1),
     ('b', 2, 2),
     ('b', 2, 3),
     ('b', 3, 1),
     ('b', 3, 2),
     ('b', 3, 3),
     ('c', 1, 1, 1),
     ('c', 1, 1, 2),
     ('c', 1, 1, 3),
     ('c', 1, 2, 1),
    ...