Finding whether a string starts with one of a list's variable-length prefixes

Question

I need to find out whether a name starts with any of a list\'s prefixes and then remove it, like:

if name[:2] in [\"i_\", \"c_\", \"m_\", \"l_\", \"d_\", \"t         


        

Answer 1

Regex, tested:

import re

def make_multi_prefix_matcher(prefixes):
    regex_text = "|".join(re.escape(p) for p in prefixes)
    print repr(regex_text)
    return re.compile(regex_text).match

pfxs = "x ya foobar foo a|b z.".split()
names = "xenon yadda yeti food foob foobarre foo a|b a b z.yx zebra".split()

matcher = make_multi_prefix_matcher(pfxs)
for name in names:
    m = matcher(name)
    if not m:
        print repr(name), "no match"
        continue
    n = m.end()
    print repr(name), n, repr(name[n:])

Output:

'x|ya|foobar|foo|a\\|b|z\\.'
'xenon' 1 'enon'
'yadda' 2 'dda'
'yeti' no match
'food' 3 'd'
'foob' 3 'b'
'foobarre' 6 're'
'foo' 3 ''
'a|b' 3 ''
'a' no match
'b' no match
'z.yx' 2 'yx'
'zebra' no match