REGEX以反向打印每个单词

Question

Could anyone please help me with the regex of reversing each word in a string?

Sample input:

Hello how are you my friend?

Desired Output

olleH woh era uoy ym ?dneirf

I want to implement this in PHP.

Answer 1

This gives you almost what you want.

If it isn't close enough, look into Blender's solution of exploding on spaces.

preg_replace_callback('/\b(\w+)\b/', function($match) {
    return strrev($match[1]);
}, $str);

CodePad.

You can reverse text using plain regex (and some string functions) but it is ugly...

$length = strlen($str);

echo preg_replace(
         '/' . str_repeat('(.)', $length) . '/s',
         '$' . join('$', range($length, 1)),
         $str
     );

CodePad.

The code sample above is for demonstration only. Please do not ever use it :)