Python: Determine prefix from a set of (similar) strings -

i have set of strings, e.g.

my_prefix_what_ever my_prefix_what_so_ever my_prefix_doesnt_matter 

i want find longest common portion of these strings, here prefix. in above result should be

my_prefix_ 

the strings

my_prefix_what_ever my_prefix_what_so_ever my_doesnt_matter 

should result in prefix

my_ 

is there relatively painless way in python determine prefix (without having iterate on each character manually)?

ps: i'm using python 2.6.3.

never rewrite provided you: os.path.commonprefix this:

return longest path prefix (taken character-by-character) prefix of paths in list. if list empty, return empty string (''). note may return invalid paths because works character @ time.

for comparison other answers, here's code:

# return longest prefix of list elements. def commonprefix(m):     "given list of pathnames, returns longest common leading component"     if not m: return ''     s1 = min(m)     s2 = max(m)     i, c in enumerate(s1):         if c != s2[i]:             return s1[:i]     return s1