Regular expression to replace all but one character in a string

Question

I need a regex to replace all matching characters except the first one squared in a string.

For instance:

To match with 'A' and replace with 'B'

To match with '' and replace with 'X'

'[space] [space] [space] A [space] [space] [space]' should be replaced by '[space] XXA [space] XX'

+4

Ammar Jun 27 '14 at 11:00

2 answers

Lookbehind

(?<!^| )A :

String resultString = subjectString.replaceAll("(?<!^| )A", "B");

.

+4

zx81 27 . '14 11:04

anubhava · Accepted Answer · 2014-06-27T11:09:35+0000

You need to use this regex to replace:

\\BA

Java:

String repl = input.replaceAll("\\BA", "B");

UPDATE. :

"(?<!^|\\w) "

:

String repl = input.replaceAll("(?<!^|\\w) ", "X");