Running through combinations of 4 numbers

Question

I need a code that would run through the possible combinations of 4 numbers e.g 1234 would produce 24 combinations of 1234, 1243, 1324 ... ect ect. But does not do ['1', '12', '123', ect] I want it to be only 4 number length combinations, (just changing the order)
A long option would be to

    import random

randomise one of the 4 numbers, randomise another and another and another, check if that combination had been printed or like added to an array that held the possible combinations and then eventually printed out all of them.

array = ['1234', '1243', '1342', '1324' ect]

That would take long though and is highly inefficient. Pretty new to coding :) Thanks

maybe this question could help: http://stackoverflow.com/questions/464864/how-to-get-all-possible-combinations-of-a-list-s-elements — boroboris, Apr 26 '17 at 09:36
@boroboris I don't want it to be '1' '12' '123' which would produce more than 24 combinations. Will add this to the description. Thank you for the suggestion though — jennmaurice, Apr 26 '17 at 09:37
@Mormin Hi Im pretty new to this. Can you explain what is wrong with my question? Thanks — jennmaurice, Apr 26 '17 at 12:05

RomanPerekhrest · Accepted Answer · 2017-04-26T10:39:58.023

7

The solution using itertools.permutations() and str.join() functions:

import itertools

n = '1234'
a = [''.join(i) for i in itertools.permutations(n, 4)]

print(a)   # prints 24 permutations

The output:

['1234', '1243', '1324', '1342', '1423', '1432', '2134', '2143', '2314', '2341', '2413', '2431', '3124', '3142', '3214', '3241', '3412', '3421', '4123', '4132', '4213', '4231', '4312', '4321']

edited Apr 26 '17 at 10:39

answered Apr 26 '17 at 09:41

RomanPerekhrest

88,541
4
65
105

Your `list` call here doesn't add anything. – DSM Apr 26 '17 at 09:59
@DSM, right, No reason for `list` call, it was for debug at start(before join). Fixed – RomanPerekhrest Apr 26 '17 at 10:41

score 1 · Answer 2 · edited May 23 '17 at 12:10

You can use the builtin module itertools in python. Refer to this question already asked here

import itertools
array = itertools.permutations([1, 2, 3, 4])

for eachpermutation in array:
    print(eachpermutation )

Should give you the output such as this

(1, 2, 3, 4)
(1, 2, 4, 3)
(1, 3, 2, 4)
(1, 3, 4, 2)
(1, 4, 2, 3)
(1, 4, 3, 2)
(2, 1, 3, 4)
(2, 1, 4, 3)
(2, 3, 1, 4)
(2, 3, 4, 1)
(2, 4, 1, 3)
(2, 4, 3, 1)
(3, 1, 2, 4)
(3, 1, 4, 2)
(3, 2, 1, 4)
(3, 2, 4, 1)
(3, 4, 1, 2)
(3, 4, 2, 1)
(4, 1, 2, 3)
(4, 1, 3, 2)
(4, 2, 1, 3)
(4, 2, 3, 1)
(4, 3, 1, 2)
(4, 3, 2, 1)

If you need to concatenate the sublists into a single number, you can use the answer provided here

for eachpermutation in array:
    print(int(''.join(str(i) for i in eachpermutation )))

gives you the following output

Hope that helps

Running through combinations of 4 numbers

2 Answers2

Linked

Related