Question

I’d like to clean up a subtitle file that has many errors because of OCR. On of the errors is that the l is displayed as I. Of course sometimes the I is really a I, mainly in the case of:

• The beginning of a sentence: I'm Ieaving... or - I'm Ieaving....
• In names: IsabeIIe.
• Maybe a few weird cases.

Since names are difficult to detect, I figured it would be best to replace only the I‘s with one or more directly preceding lowercase letters and check the rest manually. So after the conversion I get I'm Ieaving and Isabelle. This is the most ‘barebone’ automated solution I can think of since there are not that many words that have a lowercase letter directly preceding an uppercase letter.

How can I do this in Regex? Thanks in advance.

Answer 1

If your regex engine supports lookbehind, you can find all I’s preceded by a lowercase letter like this:

(?<=[a-z])I

Otherwise, you could match both characters, and the second one will be the I.

[a-z]I