Sort list of mixed strings based on digits

Question

How do I sort this list via the numerical values? Is a regex required to remove the numbers or is there a more Pythonic way to do this?

to_sort

['12-foo',
 '1-bar',
 '2-bar',
 'foo-11',
 'bar-3',
 'foo-4',
 'foobar-5',
 '6-foo',
 '7-bar']

Desired output is as follows:

1-bar
2-bar
bar-3
foo-4
foobar-5
6-foo
7-bar
foo-11
12-foo

Answer 1

One solution is the following regex extraction:

sorted(l, key=lambda x: int(re.search('\d+', x).group(0)))

---

>>> l
['12-foo', '1-bar', '2-bar', 'foo-11', 'bar-3', 'foo-4', 'foobar-5', '6-foo', '7-bar']
>>> sorted(l, key=lambda x: int(re.search('\d+', x).group(0)))
['1-bar', '2-bar', 'bar-3', 'foo-4', 'foobar-5', '6-foo', '7-bar', 'foo-11', '12-foo']

The key is the extracted digit (converted to int to avoid sorting lexographically).

Answer 2

If you don't want to use regex

>>> l = ['12-foo', '1-bar', '2-bar', 'foo-11', 'bar-3', 'foo-4', 'foobar-5', '6-foo', '7-bar']

>>> sorted(l, key = lambda x: int(''.join(filter(str.isdigit, x))))

['1-bar', '2-bar', 'bar-3', 'foo-4', 'foobar-5', '6-foo', '7-bar', 'foo-11', '12-foo']