在PHP中将一种日期格式转换为另一种格式

在PHP中是否有一种简单的方法将一种日期格式转换为另一种日期格式?

我有这个:

$old_date = date('y-m-d-h-i-s');            // works

$middle = strtotime($old_date);             // returns bool(false)

$new_date = date('Y-m-d H:i:s', $middle);   // returns 1970-01-01 00:00:00

但我当然希望它返回当前日期，而不是黎明时分。我做错了什么?

当前回答

我知道这很老了，但是，在遇到一个供应商在他们的api中不一致地使用5种不同的日期格式(并且测试了从5到最新7的各种PHP版本的服务器)时，我决定编写一个适用于无数PHP版本的通用转换器。

这个转换器几乎可以接受任何输入，包括任何标准datetime格式(包括有或没有毫秒)和任何Epoch Time表示(包括有或没有毫秒)，并将其转换为几乎任何其他格式。

称之为:

$TheDateTimeIWant=convertAnyDateTome_toMyDateTime([thedateIhave],[theformatIwant]);

为该格式发送空值将使函数返回Epoch/Unix Time格式的datetime。否则，发送date()支持的任何格式字符串，以及"。u”表示毫秒(我也处理毫秒，即使date()返回0)。

代码如下:

        <?php   
        function convertAnyDateTime_toMyDateTime($dttm,$dtFormat)
        {
            if (!isset($dttm))
            {
                return "";
            }
            $timepieces = array();
            if (is_numeric($dttm))
            {
                $rettime=$dttm;
            }
            else
            {
                $rettime=strtotime($dttm);
                if (strpos($dttm,".")>0 and strpos($dttm,"-",strpos($dttm,"."))>0)
                {
                    $rettime=$rettime.substr($dttm,strpos($dttm,"."),strpos($dttm,"-",strpos($dttm,"."))-strpos($dttm,"."));
                    $timepieces[1]="";
                }
                else if (strpos($dttm,".")>0 and strpos($dttm,"-",strpos($dttm,"."))==0)
                {               
                    preg_match('/([0-9]+)([^0-9]+)/',substr($dttm,strpos($dttm,"."))." ",$timepieces);
                    $rettime=$rettime.".".$timepieces[1];
                }
            }

            if (isset($dtFormat))
            {
                // RETURN as ANY date format sent
                if (strpos($dtFormat,".u")>0)       // Deal with milliseconds
                {
                    $rettime=date($dtFormat,$rettime);              
                    $rettime=substr($rettime,0,strripos($rettime,".")+1).$timepieces[1];                
                }
                else                                // NO milliseconds wanted
                {
                    $rettime=date($dtFormat,$rettime);
                }
            }
            else
            {
                // RETURN Epoch Time (do nothing, we already built Epoch Time)          
            }
            return $rettime;    
        }
    ?>

下面是一些示例调用-您将注意到它还处理任何时区数据(尽管如上所述，在您的时区中返回任何非GMT时间)。

        $utctime1="2018-10-30T06:10:11.2185007-07:00";
        $utctime2="2018-10-30T06:10:11.2185007";
        $utctime3="2018-10-30T06:10:11.2185007 PDT";
        $utctime4="2018-10-30T13:10:11.2185007Z";
        $utctime5="2018-10-30T13:10:11Z";
        $dttm="10/30/2018 09:10:11 AM EST";

        echo "<pre>";
        echo "<b>Epoch Time to a standard format</b><br>";
        echo "<br>Epoch Tm: 1540905011    to STD DateTime     ----RESULT: ".convertAnyDateTime_toMyDateTime("1540905011","Y-m-d H:i:s")."<hr>";
        echo "<br>Epoch Tm: 1540905011          to UTC        ----RESULT: ".convertAnyDateTime_toMyDateTime("1540905011","c");
        echo "<br>Epoch Tm: 1540905011.2185007  to UTC        ----RESULT: ".convertAnyDateTime_toMyDateTime("1540905011.2185007","c")."<hr>";
        echo "<b>Returned as Epoch Time (the number of seconds that have elapsed since 00:00:00 Thursday, 1 January 1970, Coordinated Universal Time (UTC), minus leap seconds.)";
        echo "</b><br>";
        echo "<br>UTCTime1: ".$utctime1." ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime1,null);
        echo "<br>UTCTime2: ".$utctime2."       ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime2,null);
        echo "<br>UTCTime3: ".$utctime3."   ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime3,null);
        echo "<br>UTCTime4: ".$utctime4."      ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime4,null);
        echo "<br>UTCTime5: ".$utctime5."              ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime5,null);
        echo "<br>NO MILIS: ".$dttm."        ----RESULT: ".convertAnyDateTime_toMyDateTime($dttm,null);
        echo "<hr>";
        echo "<hr>";
        echo "<b>Returned as whatever datetime format one desires</b>";
        echo "<br>UTCTime1: ".$utctime1." ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime1,"Y-m-d H:i:s")."              Y-m-d H:i:s";
        echo "<br>UTCTime2: ".$utctime2."       ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime2,"Y-m-d H:i:s.u")."      Y-m-d H:i:s.u";
        echo "<br>UTCTime3: ".$utctime3."   ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime3,"Y-m-d H:i:s.u")."      Y-m-d H:i:s.u";
        echo "<p><b>Returned as ISO8601</b>";
        echo "<br>UTCTime3: ".$utctime3."   ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime3,"c")."        ISO8601";
        echo "</pre>";

输出如下:

Epoch Tm: 1540905011                        ----RESULT: 2018-10-30 09:10:11

Epoch Tm: 1540905011          to UTC        ----RESULT: 2018-10-30T09:10:11-04:00
Epoch Tm: 1540905011.2185007  to UTC        ----RESULT: 2018-10-30T09:10:11-04:00
Returned as Epoch Time (the number of seconds that have elapsed since 00:00:00 Thursday, 1 January 1970, Coordinated Universal Time (UTC), minus leap seconds.)

UTCTime1: 2018-10-30T06:10:11.2185007-07:00 ----RESULT: 1540905011.2185007
UTCTime2: 2018-10-30T06:10:11.2185007       ----RESULT: 1540894211.2185007
UTCTime3: 2018-10-30T06:10:11.2185007 PDT   ----RESULT: 1540905011.2185007
UTCTime4: 2018-10-30T13:10:11.2185007Z      ----RESULT: 1540905011.2185007
UTCTime5: 2018-10-30T13:10:11Z              ----RESULT: 1540905011
NO MILIS: 10/30/2018 09:10:11 AM EST        ----RESULT: 1540908611
Returned as whatever datetime format one desires
UTCTime1: 2018-10-30T06:10:11.2185007-07:00 ----RESULT: 2018-10-30 09:10:11              Y-m-d H:i:s
UTCTime2: 2018-10-30T06:10:11.2185007       ----RESULT: 2018-10-30 06:10:11.2185007      Y-m-d H:i:s.u
UTCTime3: 2018-10-30T06:10:11.2185007 PDT   ----RESULT: 2018-10-30 09:10:11.2185007      Y-m-d H:i:s.u
Returned as ISO8601
UTCTime3: 2018-10-30T06:10:11.2185007 PDT   ----RESULT: 2018-10-30T09:10:11-04:00        ISO8601

这个版本中唯一没有的功能是选择希望返回的datetime所在的时区。最初，我写这个代码是为了将任何日期时间更改为Epoch Time，因此，我不需要时区支持。不过，添加起来很简单。

2019-02-01 20:34:59

其他回答

为了完整起见，我使用Carbon库添加了一个答案，Carbon库非常常见，在Laravel框架这样的大型项目中使用。

Carbon构造函数可以传递一个日期字符串(任何可以被strtotime()识别的对象)或一个DateTime对象。如果您正在处理一个不容易解析的日期字符串，Carbon提供了Carbon::createFromFormat()静态创建器方法。

$carbon = new Carbon("January 3 2025 4:28 am");
// or
$date = new \DateTime("January 3 2025 4:28 am");
$carbon = new Carbon($date);
// or
$carbon = Carbon::createFromFormat("Y-d-m/H:i", "2025-03-01/04:28");

现在你有了一个原生的Carbon对象，你可以使用Carbon::format()方法以你需要的任何格式输出它:

echo $carbon->format("l jS \\of F Y h:i A");
// Friday 3rd of January 2025 04:28 AM

有很多辅助方法可以快速输出某些格式，例如Carbon::toDateTimeString()，它以MySQL格式输出。

2021-06-09 15:06:59

这种原生方式将有助于将任何输入格式转换为所需的格式。

$formatInput = 'd-m-Y'; //Give any format here, this would be converted into your format
$dateInput = '01-02-2018'; //date in above format

$formatOut = 'Y-m-d'; // Your format
$dateOut = DateTime::createFromFormat($formatInput, $dateInput)->format($formatOut);

2018-02-07 08:38:35

下面是一个将日期转换为不同格式的简单方法。

// Create a new DateTime object
$date = DateTime::createFromFormat('Y-m-d', '2016-03-25');

// Output the date in different formats
echo $date->format('Y-m-d')."\n";
echo $date->format('d-m-Y')."\n";
echo $date->format('m-d-Y')."\n";

2016-03-25 09:11:01

这个问题解决了，

$old = '18-04-2018';
$new = date('Y-m-d', strtotime($old));
echo $new;

输出:2018-04-18

2018-04-04 18:34:55