Is it possible to remove a block comment without removing the line breaks with a regex?
Let's say I have this text:
text = """Keep this /* this has to go
this should go too but leave empty line */
This stays on line number 3"""
I came up with this regex:
text = re.sub(r'/\*.*?\*/', '', text, 0, re.DOTALL)
But this gives me:
Keep this
This stays on line number 3
What I want is:
Keep this
This stays on line number 3
Can it be done?
We can make a slight change to your current logic and use a lambda callback as the replacement for re.sub:
import re
text = """Keep this /* this has to go
this should go too but leave empty line */
This stays on line number 3"""
text = re.sub(r'/\*.*?\*/', lambda m: re.sub(r'[^\n]+', '', m.group()), text, flags=re.S)
print(text)
This prints:
Keep this
This stays on line number 3
The replacement logic in the lambda function operates on the /* ... */ comment block. It strips off all characters except for newlines, leaving the newline structure intact while removing all other content from the intermediate comment lines.
\r in [^\r\n]+ in case the input has Windows line endings (\r\n instead of just \n).