How do I remove accents from characters in a PHP string?

UTF-8 friendly version of the simple function posted above by Gino:

function stripAccents($str) {
    return strtr(utf8_decode($str), utf8_decode('àáâãäçèéêëìíîïñòóôõöùúûüýÿÀÁÂÃÄÇÈÉÊËÌÍÎÏÑÒÓÔÕÖÙÚÛÜÝ'), 'aaaaaceeeeiiiinooooouuuuyyAAAAACEEEEIIIINOOOOOUUUUY');
}

Had to come to this because my php document was UTF-8 encoded.

Hope it helps.

What about the WordPress implementation?

function remove_accents($string) {
    if ( !preg_match('/[\x80-\xff]/', $string) )
        return $string;

    $chars = array(
    // Decompositions for Latin-1 Supplement
    chr(195).chr(128) => 'A', chr(195).chr(129) => 'A',
    chr(195).chr(130) => 'A', chr(195).chr(131) => 'A',
    chr(195).chr(132) => 'A', chr(195).chr(133) => 'A',
    chr(195).chr(135) => 'C', chr(195).chr(136) => 'E',
    chr(195).chr(137) => 'E', chr(195).chr(138) => 'E',
    chr(195).chr(139) => 'E', chr(195).chr(140) => 'I',
    chr(195).chr(141) => 'I', chr(195).chr(142) => 'I',
    chr(195).chr(143) => 'I', chr(195).chr(145) => 'N',
    chr(195).chr(146) => 'O', chr(195).chr(147) => 'O',
    chr(195).chr(148) => 'O', chr(195).chr(149) => 'O',
    chr(195).chr(150) => 'O', chr(195).chr(153) => 'U',
    chr(195).chr(154) => 'U', chr(195).chr(155) => 'U',
    chr(195).chr(156) => 'U', chr(195).chr(157) => 'Y',
    chr(195).chr(159) => 's', chr(195).chr(160) => 'a',
    chr(195).chr(161) => 'a', chr(195).chr(162) => 'a',
    chr(195).chr(163) => 'a', chr(195).chr(164) => 'a',
    chr(195).chr(165) => 'a', chr(195).chr(167) => 'c',
    chr(195).chr(168) => 'e', chr(195).chr(169) => 'e',
    chr(195).chr(170) => 'e', chr(195).chr(171) => 'e',
    chr(195).chr(172) => 'i', chr(195).chr(173) => 'i',
    chr(195).chr(174) => 'i', chr(195).chr(175) => 'i',
    chr(195).chr(177) => 'n', chr(195).chr(178) => 'o',
    chr(195).chr(179) => 'o', chr(195).chr(180) => 'o',
    chr(195).chr(181) => 'o', chr(195).chr(182) => 'o',
    chr(195).chr(182) => 'o', chr(195).chr(185) => 'u',
    chr(195).chr(186) => 'u', chr(195).chr(187) => 'u',
    chr(195).chr(188) => 'u', chr(195).chr(189) => 'y',
    chr(195).chr(191) => 'y',
    // Decompositions for Latin Extended-A
    chr(196).chr(128) => 'A', chr(196).chr(129) => 'a',
    chr(196).chr(130) => 'A', chr(196).chr(131) => 'a',
    chr(196).chr(132) => 'A', chr(196).chr(133) => 'a',
    chr(196).chr(134) => 'C', chr(196).chr(135) => 'c',
    chr(196).chr(136) => 'C', chr(196).chr(137) => 'c',
    chr(196).chr(138) => 'C', chr(196).chr(139) => 'c',
    chr(196).chr(140) => 'C', chr(196).chr(141) => 'c',
    chr(196).chr(142) => 'D', chr(196).chr(143) => 'd',
    chr(196).chr(144) => 'D', chr(196).chr(145) => 'd',
    chr(196).chr(146) => 'E', chr(196).chr(147) => 'e',
    chr(196).chr(148) => 'E', chr(196).chr(149) => 'e',
    chr(196).chr(150) => 'E', chr(196).chr(151) => 'e',
    chr(196).chr(152) => 'E', chr(196).chr(153) => 'e',
    chr(196).chr(154) => 'E', chr(196).chr(155) => 'e',
    chr(196).chr(156) => 'G', chr(196).chr(157) => 'g',
    chr(196).chr(158) => 'G', chr(196).chr(159) => 'g',
    chr(196).chr(160) => 'G', chr(196).chr(161) => 'g',
    chr(196).chr(162) => 'G', chr(196).chr(163) => 'g',
    chr(196).chr(164) => 'H', chr(196).chr(165) => 'h',
    chr(196).chr(166) => 'H', chr(196).chr(167) => 'h',
    chr(196).chr(168) => 'I', chr(196).chr(169) => 'i',
    chr(196).chr(170) => 'I', chr(196).chr(171) => 'i',
    chr(196).chr(172) => 'I', chr(196).chr(173) => 'i',
    chr(196).chr(174) => 'I', chr(196).chr(175) => 'i',
    chr(196).chr(176) => 'I', chr(196).chr(177) => 'i',
    chr(196).chr(178) => 'IJ',chr(196).chr(179) => 'ij',
    chr(196).chr(180) => 'J', chr(196).chr(181) => 'j',
    chr(196).chr(182) => 'K', chr(196).chr(183) => 'k',
    chr(196).chr(184) => 'k', chr(196).chr(185) => 'L',
    chr(196).chr(186) => 'l', chr(196).chr(187) => 'L',
    chr(196).chr(188) => 'l', chr(196).chr(189) => 'L',
    chr(196).chr(190) => 'l', chr(196).chr(191) => 'L',
    chr(197).chr(128) => 'l', chr(197).chr(129) => 'L',
    chr(197).chr(130) => 'l', chr(197).chr(131) => 'N',
    chr(197).chr(132) => 'n', chr(197).chr(133) => 'N',
    chr(197).chr(134) => 'n', chr(197).chr(135) => 'N',
    chr(197).chr(136) => 'n', chr(197).chr(137) => 'N',
    chr(197).chr(138) => 'n', chr(197).chr(139) => 'N',
    chr(197).chr(140) => 'O', chr(197).chr(141) => 'o',
    chr(197).chr(142) => 'O', chr(197).chr(143) => 'o',
    chr(197).chr(144) => 'O', chr(197).chr(145) => 'o',
    chr(197).chr(146) => 'OE',chr(197).chr(147) => 'oe',
    chr(197).chr(148) => 'R',chr(197).chr(149) => 'r',
    chr(197).chr(150) => 'R',chr(197).chr(151) => 'r',
    chr(197).chr(152) => 'R',chr(197).chr(153) => 'r',
    chr(197).chr(154) => 'S',chr(197).chr(155) => 's',
    chr(197).chr(156) => 'S',chr(197).chr(157) => 's',
    chr(197).chr(158) => 'S',chr(197).chr(159) => 's',
    chr(197).chr(160) => 'S', chr(197).chr(161) => 's',
    chr(197).chr(162) => 'T', chr(197).chr(163) => 't',
    chr(197).chr(164) => 'T', chr(197).chr(165) => 't',
    chr(197).chr(166) => 'T', chr(197).chr(167) => 't',
    chr(197).chr(168) => 'U', chr(197).chr(169) => 'u',
    chr(197).chr(170) => 'U', chr(197).chr(171) => 'u',
    chr(197).chr(172) => 'U', chr(197).chr(173) => 'u',
    chr(197).chr(174) => 'U', chr(197).chr(175) => 'u',
    chr(197).chr(176) => 'U', chr(197).chr(177) => 'u',
    chr(197).chr(178) => 'U', chr(197).chr(179) => 'u',
    chr(197).chr(180) => 'W', chr(197).chr(181) => 'w',
    chr(197).chr(182) => 'Y', chr(197).chr(183) => 'y',
    chr(197).chr(184) => 'Y', chr(197).chr(185) => 'Z',
    chr(197).chr(186) => 'z', chr(197).chr(187) => 'Z',
    chr(197).chr(188) => 'z', chr(197).chr(189) => 'Z',
    chr(197).chr(190) => 'z', chr(197).chr(191) => 's'
    );

    $string = strtr($string, $chars);

    return $string;
}

To understand what this function does, check the conversion table:

À => A
Á => A
 => A
à => A
Ä => A
Å => A
Ç => C
È => E
É => E
Ê => E
Ë => E
Ì => I
Í => I
Î => I
Ï => I
Ñ => N
Ò => O
Ó => O
Ô => O
Õ => O
Ö => O
Ù => U
Ú => U
Û => U
Ü => U
Ý => Y
ß => s
à => a
á => a
â => a
ã => a
ä => a
å => a
ç => c
è => e
é => e
ê => e
ë => e
ì => i
í => i
î => i
ï => i
ñ => n
ò => o
ó => o
ô => o
õ => o
ö => o
ù => u
ú => u
û => u
ü => u
ý => y
ÿ => y
Ā => A
ā => a
Ă => A
ă => a
Ą => A
ą => a
Ć => C
ć => c
Ĉ => C
ĉ => c
Ċ => C
ċ => c
Č => C
č => c
Ď => D
ď => d
Đ => D
đ => d
Ē => E
ē => e
Ĕ => E
ĕ => e
Ė => E
ė => e
Ę => E
ę => e
Ě => E
ě => e
Ĝ => G
ĝ => g
Ğ => G
ğ => g
Ġ => G
ġ => g
Ģ => G
ģ => g
Ĥ => H
ĥ => h
Ħ => H
ħ => h
Ĩ => I
ĩ => i
Ī => I
ī => i
Ĭ => I
ĭ => i
Į => I
į => i
İ => I
ı => i
IJ => IJ
ij => ij
Ĵ => J
ĵ => j
Ķ => K
ķ => k
ĸ => k
Ĺ => L
ĺ => l
Ļ => L
ļ => l
Ľ => L
ľ => l
Ŀ => L
ŀ => l
Ł => L
ł => l
Ń => N
ń => n
Ņ => N
ņ => n
Ň => N
ň => n
ʼn => N
Ŋ => n
ŋ => N
Ō => O
ō => o
Ŏ => O
ŏ => o
Ő => O
ő => o
Π=> OE
œ => oe
Ŕ => R
ŕ => r
Ŗ => R
ŗ => r
Ř => R
ř => r
Ś => S
ś => s
Ŝ => S
ŝ => s
Ş => S
ş => s
Š => S
š => s
Ţ => T
ţ => t
Ť => T
ť => t
Ŧ => T
ŧ => t
Ũ => U
ũ => u
Ū => U
ū => u
Ŭ => U
ŭ => u
Ů => U
ů => u
Ű => U
ű => u
Ų => U
ų => u
Ŵ => W
ŵ => w
Ŷ => Y
ŷ => y
Ÿ => Y
Ź => Z
ź => z
Ż => Z
ż => z
Ž => Z
ž => z
ſ => s

You can generate the conversion table yourself by simply iterating over the $chars array of the function:

foreach($chars as $k=>$v) {
   printf("%s -> %s", $k, $v);
}

This is a piece of code I found and use often:

function stripAccents($stripAccents){
  return strtr($stripAccents,'àáâãäçèéêëìíîïñòóôõöùúûüýÿÀÁÂÃÄÇÈÉÊËÌÍÎÏÑÒÓÔÕÖÙÚÛÜÝ','aaaaaceeeeiiiinooooouuuuyyAAAAACEEEEIIIINOOOOOUUUUY');
}