Mi chiedevo, fino ad ora, perché qualcuno non avesse pubblicato una leggera modifica della risposta accettata all'uso implode()al fine di avere una migliore leggibilità del codice. Quindi ecco qui:
<?php
$uaFull = strtolower($_SERVER['HTTP_USER_AGENT']);
$uaStart = substr($uaFull, 0, 4);
$uaPhone = [
'(android|bb\d+|meego).+mobile',
'avantgo',
'bada\/',
'blackberry',
'blazer',
'compal',
'elaine',
'fennec',
'hiptop',
'iemobile',
'ip(hone|od)',
'iris',
'kindle',
'lge ',
'maemo',
'midp',
'mmp',
'mobile.+firefox',
'netfront',
'opera m(ob|in)i',
'palm( os)?',
'phone',
'p(ixi|re)\/',
'plucker',
'pocket',
'psp',
'series(4|6)0',
'symbian',
'treo',
'up\.(browser|link)',
'vodafone',
'wap',
'windows ce',
'xda',
'xiino'
];
$uaMobile = [
'1207',
'6310',
'6590',
'3gso',
'4thp',
'50[1-6]i',
'770s',
'802s',
'a wa',
'abac|ac(er|oo|s\-)',
'ai(ko|rn)',
'al(av|ca|co)',
'amoi',
'an(ex|ny|yw)',
'aptu',
'ar(ch|go)',
'as(te|us)',
'attw',
'au(di|\-m|r |s )',
'avan',
'be(ck|ll|nq)',
'bi(lb|rd)',
'bl(ac|az)',
'br(e|v)w',
'bumb',
'bw\-(n|u)',
'c55\/',
'capi',
'ccwa',
'cdm\-',
'cell',
'chtm',
'cldc',
'cmd\-',
'co(mp|nd)',
'craw',
'da(it|ll|ng)',
'dbte',
'dc\-s',
'devi',
'dica',
'dmob',
'do(c|p)o',
'ds(12|\-d)',
'el(49|ai)',
'em(l2|ul)',
'er(ic|k0)',
'esl8',
'ez([4-7]0|os|wa|ze)',
'fetc',
'fly(\-|_)',
'g1 u',
'g560',
'gene',
'gf\-5',
'g\-mo',
'go(\.w|od)',
'gr(ad|un)',
'haie',
'hcit',
'hd\-(m|p|t)',
'hei\-',
'hi(pt|ta)',
'hp( i|ip)',
'hs\-c',
'ht(c(\-| |_|a|g|p|s|t)|tp)',
'hu(aw|tc)',
'i\-(20|go|ma)',
'i230',
'iac( |\-|\/)',
'ibro',
'idea',
'ig01',
'ikom',
'im1k',
'inno',
'ipaq',
'iris',
'ja(t|v)a',
'jbro',
'jemu',
'jigs',
'kddi',
'keji',
'kgt( |\/)',
'klon',
'kpt ',
'kwc\-',
'kyo(c|k)',
'le(no|xi)',
'lg( g|\/(k|l|u)|50|54|\-[a-w])',
'libw',
'lynx',
'm1\-w',
'm3ga',
'm50\/',
'ma(te|ui|xo)',
'mc(01|21|ca)',
'm\-cr',
'me(rc|ri)',
'mi(o8|oa|ts)',
'mmef',
'mo(01|02|bi|de|do|t(\-| |o|v)|zz)',
'mt(50|p1|v )',
'mwbp',
'mywa',
'n10[0-2]',
'n20[2-3]',
'n30(0|2)',
'n50(0|2|5)',
'n7(0(0|1)|10)',
'ne((c|m)\-|on|tf|wf|wg|wt)',
'nok(6|i)',
'nzph',
'o2im',
'op(ti|wv)',
'oran',
'owg1',
'p800',
'pan(a|d|t)',
'pdxg',
'pg(13|\-([1-8]|c))',
'phil',
'pire',
'pl(ay|uc)',
'pn\-2',
'po(ck|rt|se)',
'prox',
'psio',
'pt\-g',
'qa\-a',
'qc(07|12|21|32|60|\-[2-7]|i\-)',
'qtek',
'r380',
'r600',
'raks',
'rim9',
'ro(ve|zo)',
's55\/',
'sa(ge|ma|mm|ms|ny|va)',
'sc(01|h\-|oo|p\-)',
'sdk\/',
'se(c(\-|0|1)|47|mc|nd|ri)',
'sgh\-',
'shar',
'sie(\-|m)',
'sk\-0',
'sl(45|id)',
'sm(al|ar|b3|it|t5)',
'so(ft|ny)',
'sp(01|h\-|v\-|v )',
'sy(01|mb)',
't2(18|50)',
't6(00|10|18)',
'ta(gt|lk)',
'tcl\-',
'tdg\-',
'tel(i|m)',
'tim\-',
't\-mo',
'to(pl|sh)',
'ts(70|m\-|m3|m5)',
'tx\-9',
'up(\.b|g1|si)',
'utst',
'v400',
'v750',
'veri',
'vi(rg|te)',
'vk(40|5[0-3]|\-v)',
'vm40',
'voda',
'vulc',
'vx(52|53|60|61|70|80|81|83|85|98)',
'w3c(\-| )',
'webc',
'whit',
'wi(g |nc|nw)',
'wmlb',
'wonu',
'x700',
'yas\-',
'your',
'zeto',
'zte\-'
];
$isPhone = preg_match('/' . implode($uaPhone, '|') . '/i', $uaFull);
$isMobile = preg_match('/' . implode($uaMobile, '|') . '/i', $uaStart);
if($isPhone || $isMobile) {
// do something with that device
} else {
// process normally
}