DateTime with microseconds

Question

In my code, I\'m using DateTime objects to manipulate dates, then convert them to timestamp in order to save them in some JSON files.

For some reasons,

Answer 1

This worked for me in PHP 7.2:

$dateTime = \DateTime::createFromFormat('U.u', sprintf('%f', $aFloat), $optionalTimezone);

I got to thinking that since the format code 'u' would output only the microsecond part of a date when converting to a string then doing the reverse would be the same. And that it also expects a period character '.' so if $aFloat happened to be a whole number then default conversion to a string would leave off the decimal point. Initially I thought the float to string conversion needed '%.6f' but the 'u' is expecting a string which is left justified. Trailing zeros are unnecessary.

Answer 2

$micro_seconds = microtime(false) * 1000000;
echo date('Y-m-d H:i:s.'. floor($micro_seconds));

more about date: https://www.php.net/manual/en/function.date.php

more about microtime: https://www.php.net/manual/en/function.microtime.php

Answer 3

Beautiful date and time, step by step:

Note that the microtime() tells time AND microtime (numbers after the period)

echo microtime(true) ."<br>"; //1601674357.9448
sleep(0.99);
echo microtime(true) ."<br>"; //1601674357.9449
sleep(0.99);
echo microtime(true) ."<br>"; //1601674357.945

So let's take the numbers after the period:

echo substr(microtime(true), 11,4) . "<br>"; //945

But if for a moment you only had 1 or 2 digits after the period? We complete with zeros...

Ok, now we always have 4 digits which are the microseconds

echo str_pad(substr(microtime(true), 11,4), 4, '0', STR_PAD_RIGHT) . "<br>"; //9450

So, let's add the date... Final result:

$date = gmdate('Y-m-d h:i:s.');
$time = str_pad(substr(microtime(true), 11,4), 4, '0', STR_PAD_RIGHT);

echo $date . $time; //2020-10-02 09:43:57.9450

Answer 4

Looking at a response on the PHP DateTime manual:

DateTime does not support split seconds (microseconds or milliseconds etc.) I don't know why this isn't documented. The class constructor will accept them without complaint, but they are discarded. There does not appear to be a way to take a string like "2012-07-08 11:14:15.638276" and store it in an objective form in a complete way.

So you cannot do date math on two strings such as:

<?php
$d1=new DateTime("2012-07-08 11:14:15.638276");
$d2=new DateTime("2012-07-08 11:14:15.889342");
$diff=$d2->diff($d1);
print_r( $diff ) ;

/* returns:

DateInterval Object
(
    [y] => 0
    [m] => 0
    [d] => 0
    [h] => 0
    [i] => 0
    [s] => 0
    [invert] => 0
    [days] => 0
)

*/
?>

You get back 0 when you actually want to get 0.251066 seconds.

---

However, taking a response from here:

$micro_date = microtime();
$date_array = explode(" ",$micro_date);
$date = date("Y-m-d H:i:s",$date_array[1]);
echo "Date: $date:" . $date_array[0]."<br>";

Recommended and use dateTime() class from referenced:

$t = microtime(true);
$micro = sprintf("%06d",($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"); //note "u" is microseconds (1 seconds = 1000000 µs).

Reference of dateTime() on php.net: http://php.net/manual/en/datetime.construct.php#