How to match exact "multiple" strings in Python


Question

I've got a list of exact patterns that I want to search in a given string. Currently I've got a real bad solution for such a problem.

pat1 = re.compile('foo.tralingString')
mat1 = pat1.match(mystring)

pat2 = re.compile('bar.trailingString')
mat2 = pat2.match(mystring)

if mat1 or mat2:
    # Do whatever

pat = re.compile('[foo|bar].tralingString')
match = pat.match(mystring) # Doesn't work

The only condition is that I've got a list of strings which are to be matched exactly. Whats the best possible solution in Python.

EDIT: The search patterns have some trailing patterns common.

1
13
2/10/2011 4:17:11 AM

Accepted Answer

You could do a trivial regex that combines those two:

pat = re.compile('foo|bar')
if pat.match(mystring):
    # Do whatever

You could then expand the regex to do whatever you need to, using the | separator (which means or in regex syntax)

Edit: Based upon your recent edit, this should do it for you:

pat = re.compile('(foo|bar)\\.trailingString');
if pat.match(mystring):
    # Do Whatever

The [] is a character class. So your [foo|bar] would match a string with one of the included characters (since there's no * or + or ? after the class). () is the enclosure for a sub-pattern.

20
2/10/2011 4:28:51 AM

You're right in using | but you're using a character class [] instead of a subpattern (). Try this regex:

r = re.compile('(?:foo|bar)\.trailingString')

if r.match(mystring):
    # Do stuff

Old answer

If you want to do exact substring matches you shouldn't use regex.

Try using in instead:

words = ['foo', 'bar']

# mystring contains at least one of the words
if any(i in mystring for i in words):
    # Do stuff

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