Reverse the direction of all sequences of letters in a string

Question

Is it possible to reverse only the letters in a string?

For instance if I have the word $word = "word,!";

I need the result to be $result = "drow,!";

I tried using strrev, but it reverses the punctuation marks too.

Answer 1

 $word = "word,!pineapple--pizza";
 $revd = preg_replace_callback('#([A-Za-z]+)#', 'rev_first', $word);

function rev_first($matches){
    return strrev($matches[1]);
}

http://3v4l.org/PXEs8

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