How to split python string every nth-1 + nth char

Question

For example, suppose we have a string:

'abcdefg'

And we need to get a list like this:

['ab', 'bc', 'cd', 'de', 'ef', 'fg']

we should not use any kind of library

Here is my solution:

def str_split(s):
    s = iter(s)
    ch1=''
    ch2=''
    chars_list=[]
    while True:
        try:
            ch1 = ch2 or next(s)
            ch2 = next(s)
            chars_list.append(ch1 + ch2)
        except:
            break
    return chars_list

I wonder is there a better solution? Maybe it is possible to use list comprehension like here?

@ErikR Seems to me that these chunks here are overlapping... — user2390182, May 15 '16 at 16:53

Delgan · Accepted Answer · 2016-05-15T17:10:01.890

4

You can simply use zip() and a list comprehension:

chars_list = [ch1 + ch2 for ch1, ch2 in zip(s, s[1:])]

More generally, if you need a solution for any n:

n = 3
chars_list = [s[i:i+n] for i in range(0, len(s) - n + 1, n - 1)]
# ['abc', 'cde', 'efg']

edited May 15 '16 at 17:10

answered May 15 '16 at 16:56

Delgan

18,571
11
90
141

zip works well. It is a very elegant and powerful solution.Thank you! – Eugene Alkhouski May 15 '16 at 18:09

score 0 · Answer 2 · answered May 15 '16 at 16:56

0

You could try this (hacky) solution:

def str_split(s):
    return [s[start:end] for start, end in enumerate(range(2, len(s)+1))]

Delgan's zipping solution seems more elegant though :)

answered May 15 '16 at 16:56

user2390182

72,016
6
67
89

How to split python string every nth-1 + nth char

2 Answers2