using a regex in replacement pattern

Question

I have a python pattern that I want to replace in two different ways.

Pattern: <br><b>[Ss][1-2]:[0-9]*-
1)replace by " "
2)replace s/S by Author

I can do the first one as it is a simple replacement, but I am not sure how can I do the second replacement as it depends upon input pattern and only a part of the expression has to be replaced.

This is working for case 1, where I just replace by blanks.

text="<br><b>S1:2- you are wrong. I don't think so. <br><b>S2:2- you are wrong"
newtext=re.sub("(<br><b>[Ss][1-2]:[0-9]*-)\s*", ' ',text)
print(newtext)

Can we have a variable expression in the replacement string?

Replaced text

<br><b>Author1:2- you are wrong. I don't think so. <br><b>Author2:2- you are wrong

can you give a sample replacement for the second use case

m_callens
– m_callens

2017-02-27 18:44:39 +00:00
Commented Feb 27, 2017 at 18:44 — m_callens
– m_callens, Commented Feb 27, 2017 at 18:44

akuiper · Accepted Answer · 2017-02-27 18:46:00Z

4

You may use look-around syntax:

import re
text="<br><b>S1:2- you are wrong. I don't think so. <br><b>S2:2- you are wrong"
re.sub("(?<=<br><b>)[Ss](?=[1-2]:[0-9]*-\s*)", 'Author',text)
# "<br><b>Author1:2- you are wrong. I don't think so. <br><b>Author2:2- you are wrong"

answered Feb 27, 2017 at 18:46

akuiper

216k33 gold badges362 silver badges379 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

using a regex in replacement pattern

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related