regex to filter out string

Question

I'm filtering out string using below regex

^(?!.*(P1 | P2)).*groupName.*$

Here group name is specific string which I replace at run time. This regex is already running fine.

I've two input strings which needs to pass through from this regex. Can't change ^(?!.*(P1 | P2)) part of regex, so would like to change regex after this part only. Its a very generic regex which is being used at so many places, so I have only place to have changes is groupName part of regex. Is there any way where only 2 string could pass through this regex ?

1) ADMIN-P3-UI-READ-ONLY
2) ADMIN-P3-READ-ONLY

In regex groupName is a just a variable which will be replaced at run time with required string. In this case I want 2 string to be passed, so groupName part can be replaced with READ-ONLY but it will pass 1 string too.

Can anyone suggest on this how to make this work ?

Try compiling it with `Pattern.COMMENTS` option, or prepend the pattern string with `(?x)`. — Wiktor Stribiżew, Jan 28 '21 at 11:23
@WiktorStribiżew, this is not working. Wiktor, is there any way I could check whole string more than one with one regex pattern. Like putting AND condition and if string matches all AND condtion then return true. — Kate, Jan 28 '21 at 13:27
@WiktorStribiżew, tried this...not working (?=^(?!.*(?:P1 | P2)).*Admin.*$)(?=^(?!.*(?:UI)).*$) is it correct ? — Kate, Jan 28 '21 at 13:42
I am not sure I understand the question. Do you also want to fail the strings containing `UI`? Like `^(?!.*UI)(?!.*(P1|P2)).*READ-ONLY.*$`? See [this regex demo](https://regex101.com/r/iQyd1s/1). — Wiktor Stribiżew, Jan 28 '21 at 13:47
Do you also want to fail the strings containing UI? Yes..! And why I cannot add this ^(?!.*UI) in end ? — Kate, Jan 28 '21 at 13:52
Because `^` matches the start of string. You can also use it like this: `^(?!.*UI)^(?!.*(P1|P2)).*READ-ONLY.*$` (that is, use it at the start). — Wiktor Stribiżew, Jan 28 '21 at 14:08
@Wiktor Yes working ..! but its not that much generic I was looking for..! Thanks :) — Kate, Jan 28 '21 at 15:27

Turo · Answer 1 · 2021-01-28T11:55:19.377

0

You could use negative lookBehind:

(?<!UI-)READ-ONLY

so there must be no UI- before READ-ONLY

edited Jan 28 '21 at 11:55

answered Jan 28 '21 at 11:42

Turo

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score 0 · Answer 2 · answered Jan 28 '21 at 17:43

You can add another lookahead at the very start of your pattern to further restrict what it matches because your pattern is of the "match-everything-but" type.

So, it may look like

String extraCondition = "^(?!.*UI)";
String regex = "^(?!.*(P1|P2)).*READ-ONLY.*$";
String finalRegex = extraCondition + regex;

The pattern will look like

^(?!.*UI)^(?!.*(P1|P2)).*READ-ONLY.*$

matching

^(?!.*UI) - no UI after any zero or more chars other than line break chars as many as possible from the start of string
^(?!.*(P1|P2)) - no P1 nor P2 after any zero or more chars other than line break chars as many as possible from the start of string
.*READ-ONLY - any zero or more chars other than line break chars as many as possible and then READ-ONLY
.*$ - the rest of the string. Note you may safely remove $ here unless you want to make sure there are no extra lines in the input string.

regex to filter out string

2 Answers2