Regex notepad++ and groups

Question

I have the following data in my file:

234xt_
yad42_
23ft3_
45gdw_
...

Where the _ means a space. Using Notepad++ I want to rewrite it to be:

'234xt',
'yad42',
'23ft3',
'45gdw'

I am using the following regex in the "Find what" (^\w+)\s*\n

And in the "Replace with" field $0,

But it is not working as expected.

Answer 1

You may use

^(\w+) $

or

^(\w+)\h$

And replace with '$1',.

^ will match the start of a line, (\w+) will place one or more letters, digits or underscores into Group 1 (that you may access via $1 or \1 backreference in the replacement pattern), and then a space or \h will match a space or any horizontal whitespace, and then $ will assert the position at the end of the line.

If the (white)spaces can go missing add the appropriate quantifier after the space or \h: \h* will match 0 or more whitespaces and \h? will match 1 or 0.

Settings & demo:

Answer 2

You should use \1 instead of $0 see the example in the docs.