Question

I’m trying to scour a csv with timecodes and subtitles, and change the timecode format.

For instance:

timecode_in, timecode_out, text
01:09:37.12,01:09:40.11,and we felt very close to them.

I need to replace all of the periods in the timecode with colons. But I need to filter it so it won’t change the periods in the text.

I’m thinking there should be a way to say: “Where a period has a number on each side, replace it with a colon.”

Can anybody help me with this? I have never used regular expressions before.

Answer 1

The way to say this are lookbehind and lookahead assertions

(?<=\d)\.(?=\d)

See it here on Regexr

(?<=\d) is a lookbehind assertion that ensures a digit before the current position

(?=\d) is a lookahead assertion that ensures a digit ahead of the current position

But those digits are not part of the match!