英語日付フォーマットから([January or Jan] 1st 2013 00:00 AM)からYYYY-MM-DD方式へフォーマット

date_format_std.php

<?php
/**
 * format-to-YYY-MM-DD
 *
 * @param  string $date format:[January or Jan] 1st 2013 00:00 AM
 * @return string $formatedDate format:YYYY-MM-DD hh:mm
 */
function date_format_std($date)
{
    $pattern = '/^([a-z]+)\s([a-z0-9]+)\s([0-9]{4})\s([0-2][0-9]:[0-6][0-9])\s(am|pm)/i';
    preg_match($pattern, $date, $matches);

    if (count($matches) < 1) {
        return false;
    }

    list(, $month, $day, $year, $time, $meridiem) = $matches;
    
    $monthArray = array(
        'jan'=>'01',
        'feb'=>'02',
        'mar'=>'03',
        'apr'=>'04',
        'may'=>'05',
        'jun'=>'06',
        'jul'=>'07',
        'aug'=>'08',
        'sep'=>'09',
        'oct'=>'10',
        'nov'=>'11',
        'dec'=>'12',
        'january'=>'01',
        'february'=>'02',
        'march'=>'03',
        'april'=>'04',
        'may'=>'05',
        'june'=>'06',
        'july'=>'07',
        'august'=>'08',
        'september'=>'09',
        'october'=>'10',
        'november'=>'11',
        'december'=>'12'
    );

    $month = strtolower($month);
    if (!array_key_exists($month, $monthArray)) {
        return false;
    }

    $day = (int)substr($day, 0, -2);

    if (strtolower($meridiem) === 'pm') {
        $explodeTime = explode(":", $time);
        $hour = $explodeTime[0] + 12;
        if ($hour == 24) {
            $hour = "00";
        }
        $time = $hour . ":" . $explodeTime[1];
    }
    $formatedDate = $year . '-' . $monthArray[$month] . '-' . sprintf('%02d', $day) . ' ' . $time;

    return $formatedDate;
}

// こっちのほうが良かった
function date_format_std($date)
{
    $pattern = '/^([a-z]+)\s([a-z0-9]+)\s([0-9]{4})\s([0-2][0-9]:[0-6][0-9])\s(am|pm)/i';
    if(0 === preg_match($pattern, $date)) {
        return false;
    }
    
    $meridiem = substr($date, -2);
    $datetime = substr($date, 0, -3);

    $dateTimeObj = new DateTime($datetime);
    $unixtime = $dateTimeObj->format('U');

    if ('pm' == strtolower($meridiem)) {
        $unixtime = $unixtime + 43200;
    }

    return date('Y-m-d H:i', $unixtime);
}

// strtotimeで出来た...
$datetime = 'January 3rd 2013 10:23 PM';
$date = date('Y-m-d H:i', strtotime($datetime));
//string(16) "2013-01-03 22:23"