Natural sorting in python (i.e. treat numbers as numbers)

natsort.py

items = [
	'a.5.b.1',
	'a.1.b.4',
	'a.1.b.14',
]

def natcast(item):
	if item.isdigit():
		return int(item)
	else:
		return item

def natkey(item):
	return tuple(natcast(item) for item in item.split('.'))

print(sorted(items, key=natkey))