Sorting files based on the number in them

Question

I am having few files like..

l.1,l.3,l.2,l.12,l.36,l.24

When i am sorting the list it is giving me...

l.1,l.12,l.2,l.24,l.3,l.36

How can i get them in this way?..

l.2,l.2,l.3,l.12,l.24,l.36

Note: because it is not permitting to add the actual file name as it is i ve given it as a list. but the actual file names are joined by '.' like l.1 l.2

I can write a bubble sort algorithm for that. But I want a simpler way..
Thanks

Are those `1`s (the number) or `l`s (the letter)? Also, is it a list of numbers, a list of strings, or one big string? — tobias_k, Oct 07 '13 at 08:47
Search for Python natural sort; e.g. http://stackoverflow.com/questions/4836710/does-python-have-a-built-in-function-for-string-natural-sort — iterums, Oct 07 '13 at 08:49

score 1 · Answer 1 · answered Oct 07 '13 at 08:52

1

Here you go:

  l =  ['l.1','l.3','l.2','l.12','l.36','l.24']
  sorted(l, key = lambda x: int(x[2:]))

answered Oct 07 '13 at 08:52

kofemann

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score 1 · Answer 2 · answered Oct 07 '13 at 08:53

1

In one line:

>>> li = ["l.1", "l.3", "l.2", "l.12", "l.36", "l.24"]
>>> sorted(li, key=lambda x: int(x.split(".")[-1]))
['l.1', 'l.2', 'l.3', 'l.12', 'l.24', 'l.36']

answered Oct 07 '13 at 08:53

Johannes Charra

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can u please tell me how to list files in a directory matching a sepcified string with out a for loop in a line :) – Sravan K Ghantasala Oct 07 '13 at 09:01
Filter your list first (e.g. `li = [x for x in li if "somestring" in x]`), then proceed as given above. If it's a complex pattern you want to match, use regex. – Johannes Charra Oct 07 '13 at 09:04
thanks i m implementing it now but just want to check any inbuilt function available. Thank you so much – Sravan K Ghantasala Oct 07 '13 at 09:12
Johannes it is returning me an error because my files are lsb.acct.1.. like that – Sravan K Ghantasala Oct 07 '13 at 09:15

score 0 · Answer 3 · edited Oct 07 '13 at 09:01

0

As stated in the Python documentation the sort function on a list takes multiple argument (relevant section here).

You can use the key argument to specific a function which gets the key. An implementation for you case could be:

def key_fn(n):
    return int(n.split('.')[-1])

You could then do:

l = ["l.1","l.3","l.2","l.12","l.36","l.24"]
l.sort(key=key_fn)

edited Oct 07 '13 at 09:01

Johannes Charra

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answered Oct 07 '13 at 08:56

Exelian

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Sorting files based on the number in them

3 Answers3