How to move Items from one list to the another list in python?

Question

I want to explore every possible community allocation of 10 nodes. I have total 10 items: 10 15 25 30 45 50 65 75 80 90 There are two lists (communities) c1 and c2 that I will allocate these items. Initially, I split the 10 items like following:

c1 = [10, 45, 50, 75, 90] c2 = [15, 25, 30, 65, 80]

Now I want to move one item to another list like:

c1 = [45, 50, 75, 90] c2 = [10, 15, 25, 30, 65, 80]
c1 = [10, 45, 50, 75] c2 = [15, 25, 30, 65, 80, 90]
...

I also want to move two items, three items, four items, (but not five items). Like,

c1 = [50, 75, 90] c2 = [10, 15, 25, 30, 45, 65, 80]
c1 = [10, 75, 90] c2 = [15, 25, 30, 45, 50, 65, 80]
...
c1 = [75, 90] c2 = [10, 15, 25, 30, 45, 50, 65, 80]
c1 = [10, 90] c2 = [15, 25, 30, 45, 50, 65, 75, 80]
...
c1 = [90] c2 = [10, 15, 25, 30, 45, 50, 65, 75, 80]
c1 = [45] c2 = [10, 15, 25, 30, 50, 65, 75, 80, 90]
...

I want to move every possible iterations of 1-4 items from c1 to c2 . (Total 31 possibilities: 2^5-1 ) The order inside each list doesn't matter. How can I do this?

I used the following code.

c1 = [10, 45, 50, 75, 90]
c2 = [15, 25, 30, 65, 80]

for i in c1:
    c2.append(i)
    c1.remove(i)
    print c1, c2 

With this code, I can only get following result. This code didn't accomplish the task of moving one item to c2 . My code didn't attempt to move multiple items to c2 .

[45, 50, 75, 90] [15, 25, 30, 65, 80, 10]
[45, 75, 90] [15, 25, 30, 65, 80, 10, 50]
[45, 75] [15, 25, 30, 65, 80, 10, 50, 90]

How can I successfully finish the task of moving items to c2 ? With this task, I can get every possible allocation of 10 items to two lists (ignoring cases c1==c2 ).

Answer 1

Try:

c1.append(c2.pop(i))
c1.sort()

OR

c2.append(c1.pop(i))
c2.sort()

where:

• i - index list

Answer 2

As far as I understand you are more interested in the algorithm instead of simply appending from one list to another.

There is a standard library function which provides combinations of an iterable .

It is really a good exercise to make your own combinations function.

Quick and dirty solution to your problem:

import itertools

c1 = [10, 45, 50, 75, 90]
c2 = [15, 25, 30, 65, 80]

print c1, c2
for i in range(1, 5):
    for c in itertools.combinations(c1, i):
        mc1 = sorted(list(set(c1).difference(set(c))))
        mc2 = sorted(list(set(c2).union(c)))
        print mc1, mc2

Answer 3

If you want to create every possible allocation of 10 items to 2 lists, then I would use combinations in the itertools package. For example:

import itertools
items = [10, 25, 45, 50, 15, 30, 65, 75, 80, 90]

for m in xrange(len(items)+1):
    combinations = list(itertools.combinations(items, m))
    for c1 in combinations:
       c1 = list(c1)
       c2 = list(set(items) - set(c1))
       print c1, c2

Answer 4

The following will move items from one list to another without the incorrect iterator position issue you were facing in the original problem:

c1 = [10, 45, 50, 75, 90]
c2 = [15, 25, 30, 65, 80]

while c1:
    c2.append(c1[0])
    del c1[0]
    print (c1, c2)