Create new list from old list

Question

I have a list with 5 elements, x+2, x^3+x^2+x+2, x^3+x^2+2, x^3+2x^2+2x+2, x^3+2x+2. I am trying to get a big list with elements like (x+2)(x^3+x^2+x+2), (x+2)(x^3+x^2+x+2)(x^3+x^2+2) and so on. One element multiply the other four to get a new element. The only way I know is to use For loop to do it, but it doesn't give me the right list. Here is what I have:

L = ['x+2','x^3+x^2+x+2','x^3+x^2+2','x^3+2x^2+2x+2','x^3+2x+2']

for i in range(0,len(L)): 
    for j in range(1,len(L)):
        for k in range(2,len(L)):
            for l in range(3,len(L)):
                for m in range(4,len(L)):
                    print L[i],L[j],L[k],L[l],L[m]

I have many repeat elements, I want to know to how to avoid to have those repeat elements while generate the list. Can someone tell me how to do it?

Do you want all combinations of your list? – ᴀʀᴍᴀɴ Mar 07 '16 at 19:56 — ᴀʀᴍᴀɴ, Mar 07 '16 at 19:56

ᴀʀᴍᴀɴ · Accepted Answer · 2016-03-07T20:06:56.667

You can use combinations function to get all combinations of a list:

from itertools import combinations
    result = []
    for i in range(1,len(L)):
        result.append(list(combinations(L,i))
    result # [[('x+2',), ('x^3+x^2+x+2',), ('x^3+x^2+2',), ('x^3+2x^2+2x+2',), ('x^3+2x+2',)], [('x+2', 'x^3+x^2+x+2'), ('x+2', 'x^3+x^2+2'), ('x+2', 'x^3+2x^2+2x+2'), ('x+2', 'x^3+2x+2'), ('x^3+x^2+x+2', 'x^3+x^2+2'), ('x^3+x^2+x+2', 'x^3+2x^2+2x+2'), ('x^3+x^2+x+2', 'x^3+2x+2'), ('x^3+x^2+2', 'x^3+2x^2+2x+2'), ('x^3+x^2+2', 'x^3+2x+2'), ('x^3+2x^2+2x+2', 'x^3+2x+2')], [('x+2', 'x^3+x^2+x+2', 'x^3+x^2+2'), ('x+2', 'x^3+x^2+x+2', 'x^3+2x^2+2x+2'), ('x+2', 'x^3+x^2+x+2', 'x^3+2x+2'), ('x+2', 'x^3+x^2+2', 'x^3+2x^2+2x+2'), ('x+2', 'x^3+x^2+2', 'x^3+2x+2'), ('x+2', 'x^3+2x^2+2x+2', 'x^3+2x+2'), ('x^3+x^2+x+2', 'x^3+x^2+2', 'x^3+2x^2+2x+2'), ('x^3+x^2+x+2', 'x^3+x^2+2', 'x^3+2x+2'), ('x^3+x^2+x+2', 'x^3+2x^2+2x+2', 'x^3+2x+2'), ('x^3+x^2+2', 'x^3+2x^2+2x+2', 'x^3+2x+2')], [('x+2', 'x^3+x^2+x+2', 'x^3+x^2+2', 'x^3+2x^2+2x+2'), ('x+2', 'x^3+x^2+x+2', 'x^3+x^2+2', 'x^3+2x+2'), ('x+2', 'x^3+x^2+x+2', 'x^3+2x^2+2x+2', 'x^3+2x+2'), ('x+2', 'x^3+x^2+2', 'x^3+2x^2+2x+2', 'x^3+2x+2'), ('x^3+x^2+x+2', 'x^3+x^2+2', 'x^3+2x^2+2x+2', 'x^3+2x+2')]]

@Simple , It's not an important issue , because it's an tuple with just one element , you can use `t[0]` for get ride of with `t = (something,)` — ᴀʀᴍᴀɴ, Mar 07 '16 at 20:18

score 1 · Answer 2 · edited May 23 '17 at 11:50

1

The word you're looking for is permutations

Python has that ability included in the itertools package

edited May 23 '17 at 11:50

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answered Mar 07 '16 at 20:00

en_Knight

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Create new list from old list

2 Answers2