Pythonic list reordering
in [Python]
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From: Ben Racine on 8 Apr 2010 18:52 I have a list... ['dir_0_error.dat', 'dir_120_error.dat', 'dir_30_error.dat', 'dir_330_error.dat'] I want to sort it based upon the numerical value only. Does someone have an elegant solution to this? Thanks, Ben R.
From: Chris Rebert on 8 Apr 2010 18:54 On Thu, Apr 8, 2010 at 3:52 PM, Ben Racine <i3enhamin(a)gmail.com> wrote: > I have a list... > > ['dir_0_error.dat', 'dir_120_error.dat', 'dir_30_error.dat', 'dir_330_error.dat'] > > I want to sort it based upon the numerical value only. a = ['dir_0_error.dat', 'dir_120_error.dat', 'dir_30_error.dat', 'dir_330_error.dat'] def key(item): return int(item.split('_')[1]) a.sort(key=key) Cheers, Chris -- http://blog.rebertia.com
From: Gary Herron on 8 Apr 2010 18:59 Ben Racine wrote: > I have a list... > > ['dir_0_error.dat', 'dir_120_error.dat', 'dir_30_error.dat', 'dir_330_error.dat'] > > I want to sort it based upon the numerical value only. > > Does someone have an elegant solution to this? > > Thanks, > Ben R. > How about a one liner? L.sort(key=lambda s: int(s.split('_')[1])) (Which is not necessarily elegant, but it is short.) Gary Herron
From: Joaquin Abian on 8 Apr 2010 19:01 On Apr 9, 12:52 am, Ben Racine <i3enha...(a)gmail.com> wrote: > I have a list... > > ['dir_0_error.dat', 'dir_120_error.dat', 'dir_30_error.dat', 'dir_330_error.dat'] > > I want to sort it based upon the numerical value only. > > Does someone have an elegant solution to this? > > Thanks, > Ben R. not sure about elegance, but my two cents: >> mylist = ['dir_0_error.dat', 'dir_120_error.dat', 'dir_30_error.dat', 'dir_330_error.dat'] >> mylist = [(int(item.split('_')[1]), item) for item in mylist] >> mylist.sort() >> mylist = [item for idx, item in mylist] >> mylist ['dir_0_error.dat', 'dir_30_error.dat', 'dir_120_error.dat', 'dir_330_error.dat'] joaquin
From: Lie Ryan on 8 Apr 2010 20:43
On 04/09/10 08:52, Ben Racine wrote: > I have a list... > > ['dir_0_error.dat', 'dir_120_error.dat', 'dir_30_error.dat', 'dir_330_error.dat'] > > I want to sort it based upon the numerical value only. > > Does someone have an elegant solution to this? > > Thanks, > Ben R. list.sort() and sorted() accept `key` argument, which receives a callable that transform the item to be sorted into sorting key. So if you have: l = ['dir_30_error.dat', 'dir_120_error.dat', 'dir_330_error.dat', 'dir_0_error.dat'] # 'dir_0_error.dat' -> 0 # 'dir_30_error.dat' -> 30 def getnum(s): return int(''.join(x for x in s if x.isdigit())) # sort based on getnum()'s return value l.sort(key=getnum) |