What's the correct regex for this?

Question

I want to catch Sistemas Operativos in No aprobó ni está inscripto a Sistemas Operativos (Ord. 1150). The (Ord. 1150) is optional. It can appear, or not.

Mi first try was: No aprobó ni está inscripto a (.*)( $Ord\. 1150$)? but this returned (u'Sistemas Operativos (Ord. 1150)', None).

So, what's the correct regex?

I'm using re in Python.

Update: I don't need to catch specifically the string 'Sistemas Operativos', that string is just an example. There could be any other string, but the context (No aprobó ni está inscripto a .* (Ord.1150)) will be always the same. See the comment by @DSM here.

Do you really need a regex? can't you just do `'Sistemas Operativos' in my_string` — , Dec 04 '13 at 20:47
Everyone seems to be thinking that you're just interested in knowing whether the phrase exists, but as I read you, you want "No aprobó ni está inscripto a THIS_IS_IN_ENGLISH (Ord. 1150)" to give "THIS_IS_IN_ENGLISH". Am I right, or am I overreading? — DSM, Dec 04 '13 at 20:51

arturomp · Accepted Answer · 2016-04-19T22:07:10.520

2

Try

No aprobó ni está inscripto a ([^()]*)( \(Ord\. 1150\))?

Regular expression visualization

Debuggex Demo

Then you just need to do:

import re
myString = "No aprobó ni está inscripto a Sistemas Operativos (Ord. 1150)"
result = re.search('No aprobó ni está inscripto a ([^()]*)( \(Ord\. 1150\))?', myString)
course = result.group(1) # may have a trailing space, so maybe strip()

edited Apr 19 '16 at 22:07

answered Dec 04 '13 at 20:53

arturomp

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Sé que está mal, pero estoy obteniendo esos datos de una fuente que no controlo. – sanfilippopablo Dec 04 '13 at 20:55
:( fixed the regex, though, to avoid the initial parenthesis – arturomp Dec 04 '13 at 21:01
an alternative would be `No aprobó ni está inscripto a (.*?)( $Ord\. 1150$)?` – Xavier Combelle Dec 04 '13 at 21:01

score 0 · Answer 2 · edited May 23 '17 at 12:31

The .* is greedy, meaning that it will consume as many characters as possible. Use .*? to make it lazy, thus allowing the subsequent (Ord. 1150) to match, and add a $ to the end to make sure that the entirety of the text is read (in a sense, to counteract the effects of .*?).

>>> string = u'No aprobó ni está inscripto a Sistemas Operativos (Ord. 1150)'
>>> re.match(ur'No aprobó ni está inscripto a (.*?)( \(Ord\. 1150\))?$',
        string).groups()
(u'Sistemas Operativos', u' (Ord. 1150)')

What's the correct regex for this?

2 Answers2