compare two python strings that contain numbers

Question

UPDATE: I should have specified this sooner, but not all of the names are simply floats. For example, some of them are \"prefixed\" with \"YT\". So for example\" YT1.1. so,

Answer 1

Convert the names to tuples of integers and compare the tuples:

def splittedname(s):
    return tuple(int(x) for x in s.split('.'))

splittedname(s1) > splittedname(s2)

Update: Since your names apparently can contain other characters than digits, you'll need to check for ValueError and leave any values that can't be converted to ints unchanged:

import re

def tryint(x):
    try:
        return int(x)
    except ValueError:
        return x

def splittedname(s):
    return tuple(tryint(x) for x in re.split('([0-9]+)', s))

To sort a list of names, use splittedname as a key function to sorted:

>>> names = ['YT4.11', '4.3', 'YT4.2', '4.10', 'PT2.19', 'PT2.9']
>>> sorted(names, key=splittedname)
['4.3', '4.10', 'PT2.9', 'PT2.19', 'YT4.2', 'YT4.11']