$newDate = preg_replace("/(\d+)\D+(\d+)\D+(\d+)/","$3-$2-$1",$originalDate);

此代码适用于所有日期格式。

由于您的旧日期格式，您可以更改替换变量的顺序，例如$3-$1-$2。

Note: Because this post's answer sometimes gets upvoted, I came back here to kindly ask people not to upvote it anymore. My answer is ancient, not technically correct, and there are several better approaches right here. I'm only keeping it here for historical purposes. Although the documentation poorly describes the strtotime function, @rjmunro correctly addressed the issue in his comment: it's in ISO format date "YYYY-MM-DD". Also, even though my Date_Converter function might still work, I'd like to warn that there may be imprecise statements below, so please do disregard them.

投票最多的答案其实是错误的!

PHP strtotime手册在这里声明“该函数期望得到一个包含英文日期格式的字符串”。它实际上的意思是，它期望美国日期格式，如“m-d-Y”或“m/d/Y”。

这意味着以“Y-m-d”形式提供的日期可能会被strtotime错误解释。您应该以预期的格式提供日期。

我写了一个小函数，以几种格式返回日期。随意使用和修改。如果有人真的把它变成了一个类，我很高兴它能被分享。

function Date_Converter($date, $locale = "br") {

    # Exception
    if (is_null($date))
        $date = date("m/d/Y H:i:s");

    # Let's go ahead and get a string date in case we've
    # been given a Unix Time Stamp
    if ($locale == "unix")
        $date = date("m/d/Y H:i:s", $date);

    # Separate Date from Time
    $date = explode(" ", $date);

    if ($locale == "br") {
        # Separate d/m/Y from Date
        $date[0] = explode("/", $date[0]);
        # Rearrange Date into m/d/Y
        $date[0] = $date[0][1] . "/" . $date[0][0] . "/" . $date[0][2];
    }

    # Return date in all formats
        # US
        $Return["datetime"]["us"] = implode(" ", $date);
        $Return["date"]["us"]     = $date[0];

        # Universal
        $Return["time"]           = $date[1];
        $Return["unix_datetime"]  = strtotime($Return["datetime"]["us"]);
        $Return["unix_date"]      = strtotime($Return["date"]["us"]);
        $Return["getdate"]        = getdate($Return["unix_datetime"]);

        # BR
        $Return["datetime"]["br"] = date("d/m/Y H:i:s", $Return["unix_datetime"]);
        $Return["date"]["br"]     = date("d/m/Y", $Return["unix_date"]);

    # Return
    return $Return;

} # End Function

还有一种模糊的可能性:

$oldDate = '2010-03-20'
$arr = explode('-', $oldDate);
$newDate = $arr[2].'-'.$arr[1].'-'.$arr[0];

我不知道我是否会使用它，但仍然:)

使用此函数可以从任何格式转换为任何格式

function reformatDate($date, $from_format = 'd/m/Y', $to_format = 'Y-m-d') {
    $date_aux = date_create_from_format($from_format, $date);
    return date_format($date_aux,$to_format);
}

下面给出的PHP代码使用mktime()生成明天的日期，并将其格式更改为dd/mm/yyyy格式，然后使用echo打印它。

$tomorrow = mktime(0, 0, 0, date("m"), date("d") + 1, date("Y"));
echo date("d", $tomorrow) . "/" . date("m", $tomorrow). "/" . date("Y", $tomorrow);

date('m/d/Y h:i:s a',strtotime($val['EventDateTime']));