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phpdatetime
FrancoisBaveye
FrancoisBaveye

Reputation: 1902

DateTime with microseconds

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, I want to have the same thing as DateTime (or something close), but with microseconds precision (that I would convert to float when inserting inside the JSON files).

My question is : is there a PHP object that is like DateTime, but can handle microseconds too ?

The goal is to be able to manipulate microtimes with objects.

In the date() documentation, there is something that indicates that DateTime can be created with microseconds, but I wasn't able to find how.

u Microseconds (added in PHP 5.2.2). Note that date() will always generate 000000 since it takes an integer parameter, whereas DateTime::format() does support microseconds if DateTime was created with microseconds.

I have tried to set the timestamp of a DateTime object with a floating value (microtime(true)), but it doesn't work (I think it converts the timestamp to an int, causing the loss of the microseconds).

Here is how i tried

$dt = new DateTime();
$dt->setTimestamp(3.4); // I replaced 3.4 by microtime(true), this is just to give an example
var_dump($dt);
var_dump($dt->format('u'));

The .4 is not taken into account as you can see here (even though we can use the u format, which corresponds to the microseconds).

object(DateTime)[1]
  public 'date' => string '1970-01-01 01:00:03' (length=19)
  public 'timezone_type' => int 3
  public 'timezone' => string 'Europe/Berlin' (length=13)

string '000000' (length=6)

EDIT : I saw this code, which allows to add microseconds to a DateTime, but I would need to apply a lot of modifications to the microtime before creating the DateTime. Since I will use this a lot, I want to do as little modifications to the microtime as possible before getting the "microtime object".

$d = new DateTime("15-07-2014 18:30:00.111111");

Upvotes: 40

Views: 65137

Answers (10)

Fellipe Sanches
Fellipe Sanches

Reputation: 8135

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

Upvotes: 0

Sarke
Sarke

Reputation: 3235

I'm a little late with this, but I had to develop a solution that works for PHP 5, PHP 7.0, and PHP 7.1+.

list($msec, $now) = explode(' ', microtime(false));
$z = gmdate('Y-m-d\TH:i:s' . substr($msec, 1) . '\Z', $now);

This gives you a valid UTC timestring with microseconds. If you need still need it as a DateTime object, you can just pass this string directly:

$dt = new DateTime($z);

This works from PHP 5.2 if you need the DateTime, but if you just need the string with microseconds it's good all the way back to PHP 4.

Upvotes: 0

MER
MER

Reputation: 1551

Here's a very simple method of creating a DateTime object that includes microtime.

I didn't delve into this question too deeply so if I missed something I apologize but hope you find this helpful.

$date = DateTime::createFromFormat('U.u', microtime(TRUE));
var_dump($date->format('Y-m-d H:i:s.u'));

I tested it out and tried various other ways to make this work that seemed logical but this was the sole method that worked for PHP versions prior to 7.1.

However there was a problem, it was returning the correct time portion but not the correct day portion (because of UTC time most likely) Here's what I did (still seems simpler IMHO):

$dateObj = DateTime::createFromFormat('U.u', microtime(TRUE));
$dateObj->setTimeZone(new DateTimeZone('America/Denver'));
var_dump($dateObj->format('Y-m-d H:i:s:u'));

Here's a working example: http://sandbox.onlinephpfunctions.com/code/66f20107d4adf87c90b5c8c914393d4edef180a2

UPDATE
As pointed out in comments, as of PHP 7.1, the method recommended by Planplan appears to be superior to the one shown above.

So, again for PHP 7.1 and later it may be better to use the below code instead of the above:

$dateObj = DateTime::createFromFormat('0.u00 U', microtime());
$dateObj->setTimeZone(new DateTimeZone('America/Denver'));
var_dump($dateObj->format('Y-m-d H:i:s:u'));

Please be aware that the above works only for PHP versions 7.1 and above. Previous versions of PHP will return 0s in place of the microtime, therefore losing all microtime data.

Here's an updated sandbox showing both: http://sandbox.onlinephpfunctions.com/code/a88522835fdad4ae928d023a44b721e392a3295e

NOTE: in testing the above sandbox I did not ever see the microtime(TRUE) failure which Planplan mentioned that he experienced. The updated method does, however, appear to record a higher level of precision as suggested by KristopherWindsor.

NOTE2: Please be aware that there may be rare cases where either approach will fail because of an underlying decision made regarding the handling of microseconds in PHP DateTime code. Either:

  • avoid use of this for scientific purposes or anything where a very high level of accuracy is required.
  • OR be prepared for no microsecond data to return on an exact second mark... (where a microsecond ... which is 1 millionth of a second, will have no data to return as it is complete zeros... from what I've read this is not clear from what's returned and could be done in a better way but is worth creating code to handle ... again, for high precisions uses)

Thanks for the headsup Sz. (see comments).

Upvotes: 41

diskerror
diskerror

Reputation: 21

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.

Upvotes: 1

Onitech
Onitech

Reputation: 85

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

Upvotes: 0

FrancoisBaveye
FrancoisBaveye

Reputation: 1902

/!\ EDIT /!\

I now use https://github.com/briannesbitt/Carbon, the rest of this answer is just here for historical reasons.

END EDIT

I decided to extend the class DateTime using the tips you all gave me.

The constructor takes a float (from microtime) or nothing (in this case it will be initialized with the current "micro-timestamp"). I also overrided 2 functions that were important : setTimestamp and getTimestamp.

Unfortunately, I couldn't solve the performances issue, although it's not as slow as I thought.

Here's the whole class :

<?php
class MicroDateTime extends DateTime
{
    public $microseconds = 0;

    public function __construct($time = 'now')
    {
        if ($time == 'now')
            $time = microtime(true);

        if (is_float($time + 0)) // "+ 0" implicitly converts $time to a numeric value
        {
            list($ts, $ms) = explode('.', $time);
            parent::__construct(date('Y-m-d H:i:s.', $ts).$ms);
            $this->microseconds = $time - (int)$time;
        }
        else
            throw new Exception('Incorrect value for time "'.print_r($time, true).'"');
    }

    public function setTimestamp($timestamp)
    {
        parent::setTimestamp($timestamp);
        $this->microseconds = $timestamp - (int)$timestamp;
    }

    public function getTimestamp()
    {
        return parent::getTimestamp() + $this->microseconds;
    }
}

Upvotes: 4

Błażej Krzakala
Błażej Krzakala

Reputation: 145

since I resolved my issue i want to share it with You. Php71+ have microsecconds accuracy, if You want to convert it into nano accuracy just multiply it by 1000 (10^3).

$nsTimestamp = (int) (new \DateTime())->getTimestamp() * 1000

Upvotes: 0

Valerii
Valerii

Reputation: 11

/*
 * More or less standard complete example. Tested.
 */
  private static function utime($format, $utime = null, $timezone = null) {
    if(!$utime) {
      // microtime(true) had too fiew digits of microsecconds
      $time_arr = explode( " ", microtime( false ) );
      $utime = $time_arr[1] . substr( $time_arr[0], 1, 7 );
    }
    if(!$timezone) {
      $timezone = date_default_timezone_get();
    }
    $date_time_zone = timezone_open( $timezone );
    //date_create_from_format( "U.u", $utime ) - had a bug with 3-rd parameter
    $date_time = date_create_from_format( "U.u", $utime );
    date_timezone_set( $date_time, $date_time_zone );
    $timestr = date_format( $date_time, $format );
    return $timestr;
  }

Upvotes: 1

davejal
davejal

Reputation: 6133

There are multiple options. But as already provided by Ben, I will try to give you another solution.

If you provided more details on what kind of calculations you want to do it could be changed further.

$time =microtime(true);
$micro_time=sprintf("%06d",($time - floor($time)) * 1000000);
$date=new DateTime( date('Y-m-d H:i:s.'.$micro_time,$time) );
print "Date with microseconds :<br> ".$date->format("Y-m-d H:i:s.u");

or 

$time =microtime(true);
var_dump($time);

$micro_time=sprintf("%06d",($time - floor($time)) * 1000000);
$date=new DateTime( date('Y-m-d H:i:s.'.$micro_time,$time) );
print "Date with microseconds :<br> ".$date->format("Y-m-d H:i:s.u");

or 

list($ts,$ms) = explode(".",microtime(true));
$dt = new DateTime(date("Y-m-d H:i:s.",$ts).$ms);
echo $dt->format("Y-m-d H:i:s.u");

or

list($usec, $sec) = explode(' ', microtime());
print date('Y-m-d H:i:s', $sec) . $usec;

Upvotes: 3

Ben
Ben

Reputation: 9001

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#

Upvotes: 6

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