Edit report at https://bugs.php.net/bug.php?id=61214&edit=1
ID: 61214
Comment by: 58219758 at qq dot com
Reported by: 58219758 at qq dot com
Summary: puzzled replace when replacement contains "="
Status: Not a bug
Type: Bug
Package: PCRE related
Operating System: windows 7
PHP Version: 5.3.10
Block user comment: N
Private report: N
New Comment:
Thank you very much!
Previous Comments:
------------------------------------------------------------------------
[2012-03-01 18:04:06] anon at anon dot anon
This is happening because of the fourth search expression /\w+\=([^=]+)/. It matches the previous
replacements and removes them. Without it, this:
echo preg_replace(
array('/required/', '/min\=(\d+)/', '/max\=(\d+)/'),
array('R=1', 'R="$1"', 'R="$1"'),
'required min=3 max=5 code=code'
) . "\n";
Outputs:
R=1 R="3" R="5" code=code
(As expected.) But the replacements happen one after the other instead of simultaneously, so then it
will do the equivalent of this:
echo preg_replace(
'/\w+\=([^=]+)/',
'',
'R=1 R="3" R="5" code=code'
) . "\n";
..which will match and remove 'R=1 R' and 'R="5" code', producing the
"puzzling" output:
="3" =code
Here is one way to solve it, by doing all the matches simultaneously with one regexp:
echo preg_replace_callback(
'/(\w+)(?:=(\S+))?/',
function ($parts) {
if (!empty($parts[2])) { // have '='
if ($parts[1] == 'min' || $parts[1] == 'max') {
return 'R="' . $parts[2] . '"';
} else {
return '';
}
} else {
if ($parts[1] == 'required') {
return 'R=1';
} else {
return $parts[0]; // unmodified
}
}
},
'required min=3 max=5 code=code'
) . "\n";
This outputs:
R=1 R="3" R="5"
------------------------------------------------------------------------
[2012-03-01 10:03:08] 58219758 at qq dot com
$search = array(
'/required/',
'/min\=(\d+)/',
'/max\=(\d+)/',
'/\w+\=([^=]+)/',
);
$replace2 = array(
'R=1',
'R="$1"',
'R="$1"',
);
in this case, the result is still ="3" =code
------------------------------------------------------------------------
[2012-03-01 09:59:23] 58219758 at qq dot com
"=" will be quoted to "\=", in this case, the result is R\=1 R\="3"
R\="5" too, whenever "\=" or "\\=".
------------------------------------------------------------------------
[2012-03-01 08:35:04] rasmus@php.net
This is not a bug. '=' has special meaning in ?= and ?<= expressions and it is on
the list of characters quotes by preg_quote.
------------------------------------------------------------------------
[2012-03-01 08:25:13] 58219758 at qq dot com
Description:
------------
$search =
array('/required/','/min\=(\d+)/','/max\=(\d+)/','/\w+\=([^=]+)/',);
$replace2 = array('R=1','R="$1"','R="$1"',);
It seems doesn't work correctly when replacement contains "="
Test script:
---------------
$search =
array('/required/','/min\=(\d+)/','/max\=(\d+)/','/\w+\=([^=]+)/',);
$replace1 = array('R1','R"$1"','R"$1"',);
$replace2 = array('R=1','R="$1"','R="$1"',);
$replace3 = array('R\\=1','R\\="$1"','R\\="$1"',);
$from = 'required min=3 max=5 code=code';
echo preg_replace($search, $replace1, $from);
echo preg_replace($search, $replace2, $from);
echo preg_replace($search, $replace3, $from);
Expected result:
----------------
R1 R"3" R"5"
R=1 R="3" R="5"
R\=1 R\="3" R\="5"
Actual result:
--------------
R1 R"3" R"5"
="3" =code
R\=1 R\="3" R\="5"
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=61214&edit=1