Convert datetime into date in php

I know this is old, but, in running into a vendor that inconsistently uses 5 different date formats in their APIs (and test servers with a variety of PHP versions from the 5's through the latest 7's), I decided to write a universal converter that works with a myriad of PHP versions.

This converter will take virtually any input, including any standard datetime format (including with or without milliseconds) and any Epoch Time representation (including with or without milliseconds) and convert it to virtually any other format.

To call it:

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

Sending null for the format will make the function return the datetime in Epoch/Unix Time. Otherwise, send any format string that date() supports, as well as with ".u" for milliseconds (I handle milliseconds as well, even though date() returns zeros).

Here's the code:

        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;    
        }
    ?>

Here's some sample calls - you will note it also handles any time zone data (though as noted above, any non GMT time is returned in your time zone).

        $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 "
";
        echo "Epoch Time to a standard format
";
        echo "
Epoch Tm: 1540905011    to STD DateTime     ----RESULT: ".convertAnyDateTime_toMyDateTime("1540905011","Y-m-d H:i:s")."
";
        echo "
Epoch Tm: 1540905011          to UTC        ----RESULT: ".convertAnyDateTime_toMyDateTime("1540905011","c");
        echo "
Epoch Tm: 1540905011.2185007  to UTC        ----RESULT: ".convertAnyDateTime_toMyDateTime("1540905011.2185007","c")."
";
        echo "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 "
";
        echo "
UTCTime1: ".$utctime1." ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime1,null);
        echo "
UTCTime2: ".$utctime2."       ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime2,null);
        echo "
UTCTime3: ".$utctime3."   ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime3,null);
        echo "
UTCTime4: ".$utctime4."      ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime4,null);
        echo "
UTCTime5: ".$utctime5."              ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime5,null);
        echo "
NO MILIS: ".$dttm."        ----RESULT: ".convertAnyDateTime_toMyDateTime($dttm,null);
        echo "
";
        echo "
";
        echo "Returned as whatever datetime format one desires";
        echo "
UTCTime1: ".$utctime1." ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime1,"Y-m-d H:i:s")."              Y-m-d H:i:s";
        echo "
UTCTime2: ".$utctime2."       ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime2,"Y-m-d H:i:s.u")."      Y-m-d H:i:s.u";
        echo "
UTCTime3: ".$utctime3."   ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime3,"Y-m-d H:i:s.u")."      Y-m-d H:i:s.u";
        echo "
Returned as ISO8601";
        echo "
UTCTime3: ".$utctime3."   ----RESULT: ".convertAnyDateTime_toMyDateTime($utctime3,"c")."        ISO8601";
        echo "
";

Here's the output:

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

The only thing not in this version is the ability to select the time zone you want the returned datetime to be in. Originally, I wrote this to change any datetime to Epoch Time, so, I didn't need time zone support. It's trivial to add though.

How do I change date format from YYYY