Regex search and replace substring in Python

Question

I need some help with a regular expression in python.

I have a string like this:

>>> s = '[i1]scale=-2:givenHeight_1[o1];'

How can I remove givenHeight_1 and turn the string to this?

>>> '[i1]scale=-2:360[o1];'

Is there an efficient one-liner regex for such a job?

UPDATE 1: my regex so far is something like this but currently not working:

re.sub('givenHeight_1[o1]', '360[o1]', s)

Are you going to post your regex? Also, where did _1 go? — vaultah
– vaultah, Commented Apr 29, 2015 at 15:08
Have you tried the simple string.replace? s.replace("givenHeight_1","360") — user3203010
– user3203010, Commented Apr 29, 2015 at 15:13
As @user3203010 mentions, string.replace seems better here. See stackoverflow.com/questions/5668947/… — matiasg
– matiasg, Commented Apr 29, 2015 at 15:16

Kasravnd · Accepted Answer · 2015-04-29 15:11:12Z

2

You can use positive look around with re.sub :

>>> s = '[i1]scale=-2:givenHeight_1[o1];'
>>> re.sub(r'(?<=:).*(?=\[)','360',s)
'[i1]scale=-2:360[o1];'

The preceding regex will replace any thing that came after : and before [ with an '360'.

Or based on your need you can use str.replace directly :

>>> s.replace('givenHeight_1','360')
'[i1]scale=-2:360[o1];'

answered Apr 29, 2015 at 15:11

Kasravnd

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1 Comment

I just did a simple replace as @user3203010 also suggested however I'm accepting this one for completeness and the look around trick.