I have a list [1,2,3,4,5] which I iterate over twice with for loops.
for i in list:
for j in list:
print(i,j)
I do not care about the order of i and j and therefore I receive a lot of duplicates. For example 1,2 and 2,1 are the "same" for me. Same thing for 1,4 and 4,1 and 3,5 and 5,3 and so on.
I would like to remove these duplicates but do not really understand how I should go about doing so.
Actually you want the combinations :
>>> list(combinations( [1,2,3,4,5],2))
[(1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 4), (2, 5), (3, 4), (3, 5), (4, 5)]
And as the result of itertools.combinations is a generator if you want to loop over it you don't need list :
for i,j in combinations( [1,2,3,4,5],2):
#do stuff
Also as mentioned in comments you can use itertools.combinations_with_replacement if you would like to have tuples like (n, n) :
>>> list(combinations_with_replacement([1, 2, 3, 4, 5],2))
[(1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (2, 2), (2, 3), (2, 4), (2, 5), (3, 3), (3, 4), (3, 5), (4, 4), (4, 5), (5, 5)]
itertools.combinations_with_replacement([1, 2, 3, 4, 5],2) if you would like to have tuples like (n, n) included.itertools.combinations() would produce duplicates if your list contains some. See here for detail So maybe you also should wrap it with a set ;-)
set!