删除字符串PHP中最后一个重复出现的单词

Question

I need remove last repeated word in a string, example:

Last repeat word is: all/

String input examples:

• item1/item2/all/
• item1/item2/all/all/all/
• item1/item2/all/all/all/all/

The result should be always: item1/item2/

Answer 1

If those "words" are always separated by slash, then it's as simple as a regex with a backreference:

$str = preg_replace('#\b(\w+/)\1+$#', '', $str);
           //  here \b could be written as (?<=/) more exactly

Or if all is a fixed string to look for:

$str = preg_replace('#/(all/)+$#', '/', $str);

Answer 2

I am assuming you want the last word removed, and any repeats of it

$list = explode('/', $str);
if(end($list) == '') array_pop($list); // remove empty entry on end
$last = array_pop($list);
while(end($list) == $last) array_pop($list);
$str = implode('/', $list); // put back together