blocks|key|1513328|text|这似乎是可行的，尽管http://us.php.net/date记录了微秒说明符，但并不真正支持它，这似乎是不合逻辑的：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1513329|function+getTimestamp()
{
++++++++return+date("Y-m-d\TH:i:s")+.+substr((string)microtime(),+1,+8);
}|code-block|syntax|javascript|1513330|entityMap|0|LINK|mutability|MUTABLE|url|http://us.php.net/date^0|A|M|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

This seems to work, although it seems illogical that <a href="http://us.php.net/date" rel="noreferrer">http://us.php.net/date</a> documents the microsecond specifier yet doesn't really support it:

<pre><code>function getTimestamp()
{
 return date("Y-m-d\TH:i:s") . substr((string)microtime(), 1, 8);
}
</code></pre>

blocks|key|1728791|text|您可以在构造DateTime对象时指定您的输入包含微秒，并直接使用microtime(true)作为输入。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1728792|不幸的是，如果精确到秒，这将失败，因为在microtime输出中将没有.；所以在这种情况下使用sprintf强制它包含.0：|1728793|date_create_from_format(
++++'U.u',+sprintf('%25.f',+microtime(true))
)->format('Y-m-d\TH:i:s.uO');|code-block|syntax|javascript|1728794|或者等效的(更多的OO风格)|1728795|DateTime::createFromFormat(
++++'U.u',+sprintf('%25.f',+microtime(true))
)->format('Y-m-d\TH:i:s.uO');|1728796|entityMap^0|6|8|X|F|0|Z|1|1B|7|1N|2|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|15|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|16|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|R|$]]

You can specify that your input contains microseconds when constructing a <code>DateTime</code> object, and use <code>microtime(true)</code> directly as the input.

Unfortunately, this will fail if you hit an exact second, because there will be no <code>.</code> in the microtime output; so use <code>sprintf</code> to force it to contain a <code>.0</code> in that case:

<pre><code>date_create_from_format(
 'U.u', sprintf('%.f', microtime(true))
)-&gt;format('Y-m-d\TH:i:s.uO');
</code></pre>

Or equivalently (more OO-style)

<pre><code>DateTime::createFromFormat(
 'U.u', sprintf('%.f', microtime(true))
)-&gt;format('Y-m-d\TH:i:s.uO');
</code></pre>

blocks|key|1513382|text|此函数从http://us3.php.net/date中拉出|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1513383|function+udate($format,+$utimestamp+=+null)
{
++++if+(is_null($utimestamp))
++++++++$utimestamp+=+microtime(true);

++++$timestamp+=+floor($utimestamp);
++++$milliseconds+=+round(($utimestamp+-+$timestamp)+*+1000000);

++++return+date(preg_replace('`(?<!\\\\)u`',+$milliseconds,+$format),+$timestamp);
}

echo+udate('H:i:s.u');+//+19:40:56.78128|code-block|syntax|javascript|1513384|你必须实现这个函数才能让"u“正常工作。:\|1513385|entityMap|0|LINK|mutability|MUTABLE|url|http://us3.php.net/date^0|4|N|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

This function pulled from <a href="http://us3.php.net/date" rel="noreferrer">http://us3.php.net/date</a>

<pre><code>function udate($format, $utimestamp = null)
{
 if (is_null($utimestamp))
 $utimestamp = microtime(true);

 $timestamp = floor($utimestamp);
 $milliseconds = round(($utimestamp - $timestamp) * 1000000);

 return date(preg_replace('`(?&lt;!\\\\)u`', $milliseconds, $format), $timestamp);
}

echo udate('H:i:s.u'); // 19:40:56.78128
</code></pre>

Very screwy you have to implement this function to get "u" to work... :\

blocks|key|1513558|text|试试这个，它会显示微秒数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1513559|$t+=+microtime(true);
$micro+=+sprintf("%2506d",($t+-+floor($t))+*+1000000);
$d+=+new+DateTime(+date('Y-m-d+H:i:s.'.$micro,$t)+);

print+$d->format("Y-m-d+H:i:s.u");|code-block|syntax|javascript|1513560|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this and it shows micro seconds:

<pre><code>$t = microtime(true);
$micro = sprintf("%06d",($t - floor($t)) * 1000000);
$d = new DateTime( date('Y-m-d H:i:s.'.$micro,$t) );

print $d-&gt;format("Y-m-d H:i:s.u");
</code></pre>

blocks|key|1513537|text|在Lucky的comment和这个feature+request+in+the+PHP+bug+database中，我使用的是这样的东西：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1513538|class+ExtendedDateTime+extends+DateTime+{
++++/**
+++++*+Returns+new+DateTime+object.++Adds+microtime+for+"now"+dates
+++++*+@param+string+$sTime
+++++*+@param+DateTimeZone+$oTimeZone+
+++++*/
++++public+function+__construct($sTime+=+'now',+DateTimeZone+$oTimeZone+=+NULL)+{
++++++++//+check+that+constructor+is+called+as+current+date/time
++++++++if+(strtotime($sTime)+==+time())+{
++++++++++++$aMicrotime+=+explode('+',+microtime());
++++++++++++$sTime+=+date('Y-m-d+H:i:s.'+.+$aMicrotime[0]+*+1000000,+$aMicrotime[1]);
++++++++}

++++++++//+DateTime+throws+an+Exception+with+a+null+TimeZone
++++++++if+($oTimeZone+instanceof+DateTimeZone)+{
++++++++++++parent::__construct($sTime,+$oTimeZone);
++++++++}+else+{
++++++++++++parent::__construct($sTime);
++++++++}
++++}
}

$oDate+=+new+ExtendedDateTime();
echo+$oDate->format('Y-m-d+G:i:s.u');|code-block|syntax|javascript|1513539|输出：|1513540|2010-12-01+18:12:10.146625|1513541|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/users/145709/lucky|1|https://stackoverflow.com/questions/169428/php-datetime-microseconds-always-returns-0/169458#169458|2|http://bugs.php.net/bug.php?id=49779^0|1|5|0|7|7|1|H|13|2|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]|$A|12|B|13|1|14]|$A|15|B|16|1|17]]|C|$]]|$1|D|3|E|5|F|7|18|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|19|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|1A|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|1B|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]|W|$5|P|Q|R|C|$S|X]]]]

Working from <a href="https://stackoverflow.com/users/145709/lucky">Lucky</a>'s <a href="https://stackoverflow.com/questions/169428/php-datetime-microseconds-always-returns-0/169458#169458">comment</a> and this <a href="http://bugs.php.net/bug.php?id=49779" rel="nofollow noreferrer">feature request in the PHP bug database</a>, I use something like this:

<pre><code>class ExtendedDateTime extends DateTime {
 /**
 * Returns new DateTime object. Adds microtime for "now" dates
 * @param string $sTime
 * @param DateTimeZone $oTimeZone 
 */
 public function __construct($sTime = 'now', DateTimeZone $oTimeZone = NULL) {
 // check that constructor is called as current date/time
 if (strtotime($sTime) == time()) {
 $aMicrotime = explode(' ', microtime());
 $sTime = date('Y-m-d H:i:s.' . $aMicrotime[0] * 1000000, $aMicrotime[1]);
 }

 // DateTime throws an Exception with a null TimeZone
 if ($oTimeZone instanceof DateTimeZone) {
 parent::__construct($sTime, $oTimeZone);
 } else {
 parent::__construct($sTime);
 }
 }
}

$oDate = new ExtendedDateTime();
echo $oDate-&gt;format('Y-m-d G:i:s.u');
</code></pre>

Output:

<pre><code>2010-12-01 18:12:10.146625
</code></pre>

blocks|key|1513696|text|这应该是最灵活和最精确的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1513697|function+udate($format,+$timestamp=null)+{
++++if+(!isset($timestamp))+$timestamp+=+microtime();
++++//+microtime(true)
++++if+(count($t+=+explode("+",+$timestamp))+==+1)+{
++++++++list($timestamp,+$usec)+=+explode(".",+$timestamp);
++++++++$usec+=+"."+.+$usec;
++++}
++++//+microtime+(much+more+precise)
++++else+{
++++++++$usec+=+$t[0];
++++++++$timestamp+=+$t[1];
++++}
++++//+7+decimal+places+for+"u"+is+maximum
++++$date+=+new+DateTime(date('Y-m-d+H:i:s'+.+substr(sprintf('%25.7f',+$usec),+1),+$timestamp));
++++return+$date->format($format);
}
echo+udate("Y-m-d\TH:i:s.u")+.+"\n";
echo+udate("Y-m-d\TH:i:s.u",+microtime(true))+.+"\n";
echo+udate("Y-m-d\TH:i:s.u",+microtime())+.+"\n";
/*+returns:
2015-02-14T14:10:30.472647
2015-02-14T14:10:30.472700
2015-02-14T14:10:30.472749
*/|code-block|syntax|javascript|1513698|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This should be the most flexible and precise:

<pre><code>function udate($format, $timestamp=null) {
 if (!isset($timestamp)) $timestamp = microtime();
 // microtime(true)
 if (count($t = explode(" ", $timestamp)) == 1) {
 list($timestamp, $usec) = explode(".", $timestamp);
 $usec = "." . $usec;
 }
 // microtime (much more precise)
 else {
 $usec = $t[0];
 $timestamp = $t[1];
 }
 // 7 decimal places for "u" is maximum
 $date = new DateTime(date('Y-m-d H:i:s' . substr(sprintf('%.7f', $usec), 1), $timestamp));
 return $date-&gt;format($format);
}
echo udate("Y-m-d\TH:i:s.u") . "\n";
echo udate("Y-m-d\TH:i:s.u", microtime(true)) . "\n";
echo udate("Y-m-d\TH:i:s.u", microtime()) . "\n";
/* returns:
2015-02-14T14:10:30.472647
2015-02-14T14:10:30.472700
2015-02-14T14:10:30.472749
*/
</code></pre>

blocks|key|1728570|text|使用strtotime()所接受的格式的字符串就行了！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1728571|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

String in a format accepted by strtotime()
It work!

blocks|key|1728841|text|在我正在编写的一个应用程序中，我需要在DateTime对象上设置/显示microtime。似乎让DateTime对象识别微秒的唯一方法是用"YYYY-MM-DD+HH:MM:SS.uuuuuu“格式的时间初始化它。日期和时间部分之间的空格也可以是"T“，这在ISO8601格式中很常见。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1728842|下面的函数返回一个初始化为本地时区的DateTime对象(当然可以根据需要修改代码以满足个人需求)：|1728843|//+Return+DateTime+object+including+microtime+for+"now"
function+dto_now()
{
++++list($usec,+$sec)+=+explode('+',+microtime());
++++$usec+=+substr($usec,+2,+6);
++++$datetime_now+=+date('Y-m-d+H:i:s\.',+$sec).$usec;
++++return+new+DateTime($datetime_now,+new+DateTimeZone(date_default_timezone_get()));
}|code-block|syntax|javascript|1728844|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Inside of an application I am writing I have the need to set/display microtime on DateTime objects. It seems the only way to get the DateTime object to recognize microseconds is to initialize it with the time in format of "YYYY-MM-DD HH:MM:SS.uuuuuu". The space in between the date and time portions can also be a "T" as is usual in ISO8601 format.

The following function returns a DateTime object initialized to the local timezone (code can be modified as needed of course to suit individual needs):

<pre><code>// Return DateTime object including microtime for "now"
function dto_now()
{
 list($usec, $sec) = explode(' ', microtime());
 $usec = substr($usec, 2, 6);
 $datetime_now = date('Y-m-d H:i:s\.', $sec).$usec;
 return new DateTime($datetime_now, new DateTimeZone(date_default_timezone_get()));
}
</code></pre>

blocks|key|1728910|text|基于Lucky的评论，我写了一种在服务器上存储消息的简单方法。在过去，我使用散列和增量来获得唯一的文件名，但是微秒的日期在这个应用程序中工作得很好。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1728911|//+Create+a+unique+message+ID+using+the+time+and+microseconds
++++list($usec,+$sec)+=+explode("+",+microtime());
++++$messageID+=+date("Y-m-d+H:i:s+",+$sec)+.+substr($usec,+2,+8);
++++$fname+=+"./Messages/$messageID";

++++$fp+=+fopen($fname,+'w');|code-block|syntax|javascript|1728912|这是输出文件的名称：|1728913|2015-05-07+12:03:17+65468400|1728914|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Building on Lucky’s comment, I wrote a simple way to store messages on the server. In the past I’ve used hashes and increments to get unique file names, but the date with micro-seconds works well for this application.

<pre><code>// Create a unique message ID using the time and microseconds
 list($usec, $sec) = explode(" ", microtime());
 $messageID = date("Y-m-d H:i:s ", $sec) . substr($usec, 2, 8);
 $fname = "./Messages/$messageID";

 $fp = fopen($fname, 'w');
</code></pre>

This is the name of the output file:

<pre><code>2015-05-07 12:03:17 65468400
</code></pre>

blocks|key|1728966|text|一些答案使用了几个时间戳，这在概念上是错误的，可能会出现重叠的问题：21:15:05.999的秒数加上21:15:06.000的微秒数给21:15:05.000。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1728967|显然，最简单的方法是在U.u中使用DateTime::createFromFormat()，但是as+stated+in+a+comment，如果没有微秒，它就会失败。|1728968|因此，我建议使用以下代码：|1728969|function+udate($format,+$time+=+null)+{

++++if+(!$time)+{
++++++++$time+=+microtime(true);
++++}

++++//+Avoid+missing+dot+on+full+seconds:+(string)42+and+(string)42.000000+give+'42'
++++$time+=+number_format($time,+6,+'.',+'');

++++return+DateTime::createFromFormat('U.u',+$time)->format($format);
}|code-block|syntax|javascript|1728970|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/datetime.createfromformat.php|1|https://stackoverflow.com/questions/169428/php-datetime-microseconds-always-returns-0#comment-12220584^0|Y|C|1F|C|1W|C|0|B|3|H|S|H|S|0|1C|M|1|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]]|D|@$9|1A|A|1B|1|1C]|$9|1D|A|1E|1|1F]]|E|$]]|$1|H|3|I|5|6|7|1G|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|1H|8|@]|D|@]|E|$M|N]]|$1|O|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]|W|$5|R|S|T|E|$U|X]]]]

Some answers make use of several timestamps, which is conceptually wrong, and overlapping issues may occur: seconds from <code>21:15:05.999</code> combined by microseconds from <code>21:15:06.000</code> give <code>21:15:05.000</code>.

Apparently the simplest is to use <a href="http://php.net/manual/en/datetime.createfromformat.php" rel="nofollow noreferrer"><code>DateTime::createFromFormat()</code></a> with <code>U.u</code>, but <a href="https://stackoverflow.com/questions/169428/php-datetime-microseconds-always-returns-0#comment-12220584">as stated in a comment</a>, it fails if there are no microseconds.

So, I'm suggesting this code:

<pre><code>function udate($format, $time = null) {

 if (!$time) {
 $time = microtime(true);
 }

 // Avoid missing dot on full seconds: (string)42 and (string)42.000000 give '42'
 $time = number_format($time, 6, '.', '');

 return DateTime::createFromFormat('U.u', $time)-&gt;format($format);
}
</code></pre>

blocks|key|1513484|text|仅PHP+5.2支持日期(‘u’)。您的PHP可能比较旧！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1513485|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

date('u') is supported only from PHP 5.2. Your PHP may be older!

this code always returns 0 in PHP 5.2.5 for microseconds:

<pre><code>&lt;?php
$dt = new DateTime();
echo $dt-&gt;format("Y-m-d\TH:i:s.u") . "\n";
?&gt;
</code></pre>

Output:

<pre><code>[root@www1 ~]$ php date_test.php
2008-10-03T20:31:26.000000
[root@www1 ~]$ php date_test.php
2008-10-03T20:31:27.000000
[root@www1 ~]$ php date_test.php
2008-10-03T20:31:27.000000
[root@www1 ~]$ php date_test.php
2008-10-03T20:31:28.000000
</code></pre>

Any ideas?

PHP DateTime microseconds always returns 0

服务器

在PHP 5.2.5中，此代码始终以微秒为单位返回0：<?php$dt = new DateTime();echo $dt->format("Y-m-d\TH:i:s.u") . "\n";?>输出：[root@www1 ~]$ php date_test.php2008-10-03T20:31:26.000000[root@www1 ~]$ php date_test.php2008-10-03

问PHP DateTime微秒总是返回0
EN

回答 11

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问PHP DateTime微秒总是返回0EN

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问PHP DateTime微秒总是返回0
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