Replace only the last matched string with preg replace php

Question

I have this string :

use A\B\C;
use A\B\C;

var $foo;
/*
* comment
*/

use D\E\F;

Class Foo {

How i can replace the last string that beginning with use. In example above must be "use D\E\F;" as the result.

I have found many ways but no luck. including with lookahead negative (?!) but was confused how to use it. So this the i can get now " use(.*); " but this was replaced all the matched string.

Thanks.

anubhava · Accepted Answer · 2014-03-12 03:36:08Z

1

You can use this regex with s switch (DOTALL) for search:

'/use [^\n]*(?!.*?use)/s'

Online Demo: http://regex101.com/r/dX9hQ9

Code:

$re = '/use [^\n]*(?!.*?use)/s'; 
$str = 'use A\B\C;
use A\B\C;
var $foo;
/*
* comment
*/
use D\E\F;
Class Foo {'; 

preg_match($re, $str, $matches);

Explanation:

s modifier makes dot match new lines
use [^\n]* matches text use untile new line is found
(?!.*?use) is a Negative Lookahead which matches previous regex only if it is not followed by another use

edited Mar 12, 2014 at 3:36

answered Mar 12, 2014 at 3:16

anubhava

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3 Comments

mockie Over a year ago

can you explain it a bit more.. i will very apreciate it. btw thanks for the answer :) .

mockie Over a year ago

ahhh okay... i see the bottom of your link.. there is explanation there.. thanks ;)

anubhava Over a year ago

Yes I added but regex101 has quite a detailed explanation.

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Replace only the last matched string with preg replace php

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