ID: 47232
User updated by: michael dot moussa at gmail dot com
Reported By: michael dot moussa at gmail dot com
Status: Bogus
Bug Type: Strings related
Operating System: *
PHP Version: 5.2.8
New Comment:
Jani,
The documentation says "This function returns a string or an array
with all occurrences of search in subject replaced with the given
replace value."
Refer to the following example:
$subject = 'A';
echo str_replace( array('A','B','C','D'), array('B','C','D','E'),
$subject);
The result is 'E'. If str_replace() is replacing occurrences in
*$subject*, then how do we end up with 'E' if 'D' doesn't exist in
$subject? The result SHOULD be 'B'. $subject is 'A', so the first
replacement replaces 'A' with 'B'. The second replacement, as the
documentation states, should check for occurrences of 'B' within
$subject, *NOT* within str_replace('A', 'B', $subject) - and so on.
If this result is not a bug, then the documentation should be updated
to indicate that subsequent replacements are done on the result of
the previous replacement operation.
Thanks
Previous Comments:
------------------------------------------------------------------------
[2009-01-28 22:50:33] [email protected]
I mistakenly _deleted_ your comment in the manual when I was supposed
to edit it and add a note about preg_replace() there as well. Sorry
for the inconvenience, but can you readd it? (that stupid comment
moderator thing should ask "are you sure" before actually deleting
stuff..)
------------------------------------------------------------------------
[2009-01-28 22:47:05] [email protected]
Maybe this is a bit confusing but I do understand it exactly like
that:
"If search or replace are arrays, their elements are processed first
to last."
So in:
a b c d e
b c d e f
1st pass: b b c d e
2nd pass: c c c d e
3rd pass: d d d d e
4th pass: e e e e e
5th pass: f f f f f
If it did not work like it does, it would not do what it's expected
to do. Use preg_replace() instead with proper regexps. str_replace()
is the quick'n' dirty method..
------------------------------------------------------------------------
[2009-01-28 18:56:10] michael dot moussa at gmail dot com
Description:
------------
When $search and $replace are arrays, str_replace factors previous
replacements into the process and produces unexpected input.
Reproduce code:
---------------
<?php
$search = array('A', 'B', 'C', 'D', 'E');
$replace = array('B', 'C', 'D', 'E', 'F');
echo str_replace($search, $replace, 'ABCDE');
?>
Expected result:
----------------
Each letter in the string 'ABCDE' should be replaced by the letter that
follows it in the alphabet, that is, A should be replaced with B, B
should be replaced with C, etc...
The expected result is 'BCDEF'
Actual result:
--------------
The actual result is 'FFFFF'. The documentation does not indicate that
$subject is continuously updated as the process moves along.
A more practical example:
echo str_replace(
array(" ", "&"),
array(" ", "&"),
"Hello & goodbye!"
);
This should replace "Hello & goodbye!" with
"Hello & goodbye!" but it actually results in
"Hello&nbsp&&nbspgoodbye!", as the original replacement of "
" with " " introduced an additional ampersand.
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=47232&edit=1
