regex replacing at beginning of line in notepad++

Question

for example I have txt with content

qqqqaa
qqss
ss00

I want to replace only one q at the beginning of line, that is to get

qqqaa
qss
ss00

I tried replace ^q in notepad++. But After I click replaceAll, I got

aa
ss
ss00

What is wrong? Is my regex wrong? What is the correct form?

Answer 1

The issue is that Notepad++ Replace All functionality replaces in a loop using the modified document.

The solution is to actually consume what we need to replace and keep within one regex expression like

^q(q*)

and replace with $1.

The pattern will find a q at the beginning of the line and then will capture into Group 1 zero or more occurrences of q after the first q, and in the replacement part the $1 will insert these qs inside Group 1 back into the string.

Answer 2

You can use ^q(.+) and replace with $1 if you also want to replace single q's.