Python re expression conditional match

Question

To capture both of the following expressions:

str1 = "my son is 21 now"
str2 = "son is 21 now"

These two re statements and filters each capture one respectively:

r1 = re.compile(".* (son)\s+(is)\s+(21) .*")
r2 = re.compile("(son)\s+(is)\s+(21) .*")

m1 = filter(r1.match, [str1, str2])
m2 = filter(r2.match, [str1, str2])

How would I combine r1 and r2 into one re statement such that both strings will be matched?

Wiktor Stribiżew · Accepted Answer · 2015-07-13 16:45:21Z

1

I guess the easiest is to make the first capturing group optional in the first regex:

(.* )?(son)\s+(is)\s+(21) .*

See demo

answered Jul 13, 2015 at 16:45

Wiktor Stribiżew

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Comments

Avinash Raj · Accepted Answer · 2015-07-13 16:42:46Z

0

Just put ^, .* inside a group delimited by pipe symbol at the start.

r1 = re.compile(r"(?:^|.* )(son)\s+(is)\s+(21) .*")

edited Jul 13, 2015 at 16:42

answered Jul 13, 2015 at 16:35

Avinash Raj

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2 Comments

Leb Over a year ago

Wouldn't the additional spaces in there cause issues? (?:^|.*)(son)\s+(is)\s+(21).*")

Avinash Raj Over a year ago

@Leb yep. without the space , fooson is 21 will got a match.

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