Edit report at http://bugs.php.net/bug.php?id=52118&edit=1
ID: 52118
Comment by: tomasz dot slominski at gmail dot com
Reported by: tomasz dot slominski at gmail dot com
Summary: preg_replace gives bad output if matching group equals
whole string
Status: Bogus
Type: Bug
Package: *Regular Expressions
Operating System: WIN XP SP3
PHP Version: Irrelevant
New Comment:
ok, but shouldn't greedy .* consume the whole string?
var_dump(preg_replace("/(.*)/U", '$1!','test'));
gives
string '!t!!e!!s!!t!!' (length=13)
and that's ok, but why
var_dump(preg_replace("/(.*)/", '$1!','test'));
is producing
string 'test!!' (matching 'test' - nothing)
instead of
string '!test!!' (matching nothing - 'test' - nothing) or string
'test!'
(matching 'test')
it's at least counter-intuitive
Previous Comments:
------------------------------------------------------------------------
[2010-06-18 12:04:20] [email protected]
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php
This is expected behaviour. When a match is found, PCRE checks for the
next
possible match starting at the point immediately after the previous
match. In
your case, the .* first matches the entire subject string "test", then
also
matches again at very end of the string since the * quantifier allows
matching
nothing.
------------------------------------------------------------------------
[2010-06-18 11:40:13] tomasz dot slominski at gmail dot com
Fast hack: var_dump(preg_replace(array("/(.+)(.*)/"),
array('!$1$2'),'test'));
gives good output (!test)
------------------------------------------------------------------------
[2010-06-18 11:25:37] tomasz dot slominski at gmail dot com
Description:
------------
preg replace is going mad when matching group equals to (.*). It seems
that
substitution is made 2 times instead of 1.
Test script:
---------------
var_dump(preg_replace(array("/(.*)/"), array('!$1'),'test'));
var_dump(preg_replace(array("/(.*)/"), array('$1!'),'test'));
var_dump(preg_replace(array("/(.*)/"), array('!$1!'),'test'));
Expected result:
----------------
string '!test' (length=5)
string 'test!' (length=5)
string '!test!' (length=6)
Actual result:
--------------
string '!test!' (length=6)
string 'test!!' (length=6)
string '!test!!!' (length=8)
------------------------------------------------------------------------
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Edit this bug report at http://bugs.php.net/bug.php?id=52118&edit=1
