Natural order sorting strings with numbers
The following python code makes natural sorting sequences of lexical and numerical values a little easier. It supports any iterable containing strings which have embedded numbers. In short it would give you this:
foo1 < foo2 < foo10
instead of this:
foo1 < foo10 < foo2
As an example, if you have this sequence:
>>> seq = ['foo', 'foo1', 'foo2', 'foo10', 'foobar10', '20', '100', '1', '3', 'bar1']a regular sort would produce this:
>>> sorted(seq)
['1', '100', '20', '3', 'bar1', 'foo', 'foo1', 'foo10', 'foo2', 'foobar10']whereas a natural sort would produce this:
>>> natural_sort(seq)
['1', '3', '20', '100', 'bar1', 'foo', 'foo1', 'foo2', 'foo10', 'foobar10']Here is the code:
import re
def natsort_key(item):
chunks = re.split('(\d+(?:\.\d+)?)', item)
for ii in range(len(chunks)):
if chunks[ii] and chunks[ii][0] in '0123456789':
if '.' in chunks[ii]: numtype = float
else: numtype = int
chunks[ii] = (0, numtype(chunks[ii]))
else:
chunks[ii] = (1, chunks[ii])
return (chunks, item)
def natural_sort(seq):
sortlist = [item for item in seq]
sortlist.sort(key=natsort_key)
return sortlist