Python regex, how to search for multiple strings?

Question

I'm new to python and am trying to figure out python regex to find any strings that match -. For example, 'type1-001' and 'type2-001' should be a match, but 'type3-asdf001' shouldn't be a match. I would like to be able to match with a regex like [type1|type2|type3]-\d+ to find any strings that start with type1, type2, or type3 and then are appended with '-' and digits. Also, it would be cool to know how to search for any upper case text appended with '-' and digits.

Here's what I think should work, but I can't seem to get it right...

pref_num = re.compile(r'[type1|type2]-\d+')

Just FYI here, but a regex that searches for multiple strings is kind of redundant, as the whole point of a regex is to search for multiple strings. If you were only searching for one string, you could test for membership with in, and the match would simply be the string itself. — TigerhawkT3
– TigerhawkT3, Commented May 20, 2015 at 17:43
@TigerhawkT3 Not really. I can give you regexes that search for a single static string but includes multiple conditions that are not possible using a simple text search. — poke
– poke, Commented May 20, 2015 at 17:47
@poke nailed it, my example is simplified, but i need to search for single static strings that include multiple conditions that aren't possible with simple text search (without keeping/updating a list of all of those strings) — user797963
– user797963, Commented May 20, 2015 at 18:11

Jason Aller · Accepted Answer · 2018-05-31 23:14:01Z

3

[] will match any of the set of characters appearing between the brackets. To group regexes you need to use (). So, I think your regex should be something like:

pref_num = re.compile(r'(type1|type2)-\d+')

As to how to search any uppercase text appended with - and digits, I would suggest:

[A-Z]+-\d+

edited May 31, 2018 at 23:14

Jason Aller

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answered May 20, 2015 at 17:51

Josep J.

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1 Comment

user797963 Over a year ago

Thanks, this answers both of my questions. Perfect. Also, the () vs [] was key to matching the group regex.

junnytony · Accepted Answer · 2015-05-20 17:40:02Z

2

If you only want the digit after "type" to be variable then you should put only those in the square brackets like so:

re.compile(r'type[1|2]-\d+')

answered May 20, 2015 at 17:40

junnytony

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Comments

Cory Kramer · Accepted Answer · 2015-05-20 17:39:52Z

0

You can use the pattern

'type[1-3]-[0-9]{3}'

Demo

>>> import re
>>> p = 'type[1-3]-[0-9]{3}'
>>> s = 'type2-005 with some text type1-101 and then type1-asdf001'
>>> re.findall(p, s)
['type2-005', 'type1-101']

answered May 20, 2015 at 17:39

Cory Kramer

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Comments

lit · Accepted Answer · 2015-05-20 17:50:03Z

0

pref_num = re.compile(r'(type1|type2|type3)-\d+')

m = pref_num.search('type1-000')
if m != None: print(m.string)

m = pref_num.search('type2-000')
if m != None: print(m.string)

m = pref_num.search('type3-abc000')
if m != None: print(m.string)

answered May 20, 2015 at 17:50

lit

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