PHP undefined chars ? in output [closed]

问题

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Closed 6 years ago.

My problem is that i dont know from where those chars in my output, can anyone explain me why in my string are those characters and what ive to do to unset them ?

the function is used to change 'ä', 'ö', 'ü' into 'ae', 'oe', 'ue'

<?php

// str      | string argument
// needle   | searched char
// val      | value
// pos      | default 0 at start at offset zero 
// pos      | momently just working with default offset
function changeLetter($str, $needle, $val, $pos = 0) {
    $mstr = "";
    while (isset($str[$pos])) {            
        if (ord($str[$pos]) == ord($needle)) {
            $mstr .= $val;
            $pos++;
        } else {
            $mstr .= $str[$pos];
            $pos++;
        }
    }
    return $mstr;
}

echo changeLetter("täp@tecmax.com", 'ä', 'ae') . '<br>';
echo changeLetter("tüp@tecmax.com", 'ü', 'ue') . '<br>';
echo changeLetter("töp@tecmax.com", 'ö', 'oe') . '<br>';


//echo changeLetter("täp@tecmax.com", 'ä', 'ae', 3) . '<br>';   
?>

Output:

tae�p@tecmax.com

tue�p@tecmax.com

toe�p@tecmax.com

回答1:

Here is what you can do :

echo changeLetter("täp@tecmax.com", 'ä', 'ae'), PHP_EOL;
echo changeLetter("tüp@tecmax.com", 'ü', 'ue'), PHP_EOL;
echo changeLetter("töp@tecmax.com", 'ö', 'oe'), PHP_EOL;

Output

taep@tecmax.com
tuep@tecmax.com
toep@tecmax.com

Function Used

function changeLetter($str, $needle, $val, $pos = 0) {
    $next = function ($str, &$pos) {
        if (! isset($str[$pos]))
            return false;
        $char = ord($str[$pos]);
        if ($char < 128) {
            return $str[$pos ++];
        } else {
            if ($char < 224) {
                $bytes = 2;
            } elseif ($char < 240) {
                $bytes = 3;
            } elseif ($char < 248) {
                $bytes = 4;
            } elseif ($char = 252) {
                $bytes = 5;
            } else {
                $bytes = 6;
            }
            $str = substr($str, $pos, $bytes);
            $pos += $bytes;
            return $str;
        }
    };
    $mstr = "";
    while(($chr = $next($str, $pos)) !== false) {
        $mstr .= $chr == $needle ? $val : $chr;
    }
    return $mstr;
}

回答2:

you need to change your file encoding, or use ä, ü, ö instead of ä, ü, ö.

来源：https://stackoverflow.com/questions/16718705/php-undefined-chars-in-output