Splitting list Python

Question

I have the list which looks something of this sort. I wanted to know if there is any quick way to create sub list out of this?

list = [1,2,3,4,5,6,7,8,.....]

What is the best way in python to split list into this sublist?

1. [(1, 2), (3, 4), (5, 6), ...]
2. [(1, 2, 3), (4, 5, 6), ...]
3. [(1,2,3,4),(5,6,7,8), ....]

Is there some sort of pattern here or programatic splitting? Or do you just want to know operations for creating sublists of lists? — woemler, Jul 03 '13 at 03:03
Yeah. I am just taking list as an example..NO patterns as such.. just searching for a method to do it .. — user2510612, Jul 03 '13 at 03:03

grc · Accepted Answer · 2013-07-03T03:11:20.237

You can achieve this quite easily by looping over the list with a step equivalent to the number of elements you want in each sublist (e.g. range(0, len(a), n)). You can extract the elements you need for each sublist using indexing (e.g. a[i:i+n]). For example:

def group(a, n):
    return [tuple(a[i:i+n]) for i in range(0, len(a), n)]


print group([1, 2, 3, 4, 5, 6], 2)
# [(1, 2), (3, 4), (5, 6)]

print group([1, 2, 3, 4, 5, 6], 3)
# [(1, 2, 3), (4, 5, 6)]

print group([1, 2, 3, 4, 5, 6, 7, 8], 4)
# [(1, 2, 3, 4), (5, 6, 7, 8)]

score 0 · Answer 2 · 2013-07-03T03:07:55.923

0

Try numpy.reshape:

>>> import numpy
>>> a = range(1,7)
>>> a
[1, 2, 3, 4, 5, 6]
>>> numpy.reshape(a,(3,2))
array([[1, 2],
       [3, 4],
       [5, 6]])
>>> numpy.reshape(a,(2,3))
array([[1, 2, 3],
       [4, 5, 6]])

reshape takes an "array like" object and a tuple containing the numbers of rows and columns of the new matrix.

edited Jul 03 '13 at 03:07

answered Jul 03 '13 at 03:00

Splitting list Python

2 Answers2