How can I match any substring except a particular one in python

Question

I want to write a regular expression that will match the following string

a (any substring except 'ABC') ABC

An example for this would be a pqrs h js ABC The tricky part is to match any substring except 'ABC'. Since the document in which I am searching for, can contain multiple lines that contain such pattern and I want to find all the lines separately I can't use the following expression

a.*ABC

because this would just give me the line where the first a is found extending uptill where the last 'ABC' is found in the document.

There is this answer which says I can use look ahead negation but that is not working in python, or maybe in my case because there is substring before and I have not tested simply using that expression because it will not serve my purpose

I think I have made it clear I want to find all the indices where such pattern exists. I will make use of .finditer to get all such locations in the document. — Sachin, Mar 07 '12 at 16:19
Please see the lines that I have made bold in my question, I feel that I had made it clear what I want to achieve — Sachin, Mar 07 '12 at 16:50
I would not like to argue with you. Anyways I have got my answer, so at least my question was clear to others — Sachin, Mar 07 '12 at 16:56

score 2 · Accepted Answer · answered Mar 07 '12 at 14:50

2

Use the non greedy quantifier i.e ?

^a.*?ABC

answered Mar 07 '12 at 14:50

Toto

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Thanks a lot, It worked. I am new at regular expressions, if possible can you explain why `?` is called non greedy quantifier – Sachin Mar 07 '12 at 16:22
1

@Sachin: Have a look at this site http://www.regular-expressions.info/tutorial.html , it will explain better than I. – Toto Mar 07 '12 at 16:31

How can I match any substring except a particular one in python

1 Answers1