note 97989 added to function.str-replace

If you're using an array for $search and have elements that are substrings of other elements, make sure that you place the longer strings at the beginning of the array.

The following is a snippet where I wanted to replace all combinations of returns with a BR tag. 

<?

$search = array("\n", "\r", "\n\r", "\r\n");
$replace = "<BR>";

$some_string = "abc \n def \r hij \n\r klm \r\n nop";

echo str_replace($search, $replace, $some_string); // INCORRECT: Echos "abc <BR> def <BR> hij <BR><BR> klm <BR><BR> nop"

$search_correct = array("\n\r", "\r\n", "\n", "\r");

echo str_replace($search_correct, $replace, $some_string); // CORRECT: Echos "abc <BR> def <BR> hij <BR> klm <BR> nop"

?>

In the first echo, the string "\n\r" is being replaced by "\n" then by "\r" instead of being matched with "\n\r". When the order is changed in the second echo to have the longer strings before the less specific ones, everything goes peachy.

My two guesses as to what is internally happening is that either PHP loops over $search and calls str_replace for each element, or PHP uses first match instead of best match (longest match) replacement for efficiency reasons.
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Probable Submitter: 70.129.225.173
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Manual Page -- http://www.php.net/manual/en/function.str-replace.php
Edit        -- https://master.php.net/note/edit/97989
Del: integrated  -- https://master.php.net/note/delete/97989/integrated
Del: useless     -- https://master.php.net/note/delete/97989/useless
Del: bad code    -- https://master.php.net/note/delete/97989/bad+code
Del: spam        -- https://master.php.net/note/delete/97989/spam
Del: non-english -- https://master.php.net/note/delete/97989/non-english
Del: in docs     -- https://master.php.net/note/delete/97989/in+docs
Del: other reasons-- https://master.php.net/note/delete/97989
Reject      -- https://master.php.net/note/reject/97989
Search      -- https://master.php.net/manage/user-notes.php