Convert hour to timestamp php

IMPORTANT:

In addition to above answers ,there is an important thing that one must follow.Always use the With() function(see below) i.e

Always use :

$newTimezone = new DateTime($day);
$newTimezone->setTimezone(new DateTimeZone($timezone)); 

Do not use:

$newTimezone = new DateTime($day, new DateTimeZone($timezone));

REASON:(different outputs, check below)

function with($day,$timezone){
    $newTimezone = new DateTime($day);
    $newTimezone->setTimezone(new DateTimeZone($timezone)); 
    $timestamp = $newTimezone->format('U');
    return $timestamp;

}    
function without($day,$timezone){
    $newTimezone = new DateTime($day, new DateTimeZone($timezone));
    $timestamp = $newTimezone->format('U');
    return $timestamp;
}   
     
$tomorrow = date('Y-m-d h:i:s A', strtotime('-1 seconds ' ,strtotime('tomorrow midnight')));
$yesterday = date('Y-m-d h:i:s A', strtotime('+24 hours 1 seconds ' , strtotime('yesterday midnight')));
$timezone = 'UTC';
        


echo 'With Yesterday: '.with($yesterday,$timezone).'
';
    $now = new DateTime('@'.with($yesterday,$timezone));
    $now->setTimezone(new DateTimeZone(date_default_timezone_get()));
    echo 'With Yesterday Readable: '.$now->format('m/d/Y h:i:s A').' -------- '.date('m/d/Y h:i:s A').'

'; 

echo 'Without Yesterday: '.without($yesterday,$timezone).'
';
    $now = new DateTime('@'.without($yesterday,$timezone));
    $now->setTimezone(new DateTimeZone(date_default_timezone_get()));
    echo 'With Yesterday Readable: '.$now->format('m/d/Y h:i:s A').' -------- '.date('m/d/Y h:i:s A').'

'; 


echo 'With Tomorrow: '.with($tomorrow,$timezone).'
';
    $now = new DateTime('@'.with($tomorrow,$timezone));
    $now->setTimezone(new DateTimeZone(date_default_timezone_get()));
    echo 'With Yesterday Readable: '.$now->format('m/d/Y h:i:s A').' -------- '.date('m/d/Y h:i:s A').'

'; 


echo 'Without Tomorrow: '.without($tomorrow,$timezone).'
';
    $now = new DateTime('@'.without($tomorrow,$timezone));
    $now->setTimezone(new DateTimeZone(date_default_timezone_get()));
    echo 'With Yesterday Readable: '.$now->format('m/d/Y h:i:s A').' -------- '.date('m/d/Y h:i:s A').'

'; 

OUTPUTS:

With Yesterday: 1537642801

With Yesterday Readable: 09/23/2018 12:00:01 AM -------- 09/23/2018 10:05:55 PM

Without Yesterday: 1537660801

With Yesterday Readable: 09/23/2018 05:00:01 AM -------- 09/23/2018 10:05:55 PM

With Tomorrow: 1537729199

With Yesterday Readable: 09/23/2018 11:59:59 PM -------- 09/23/2018 10:05:55 PM

Without Tomorrow: 1537747199

With Yesterday Readable: 09/24/2018 04:59:59 AM -------- 09/23/2018 10:05:55 PM

The easiest (and most reliable) way to store the time in a database table is with a timestamp. It is also the most convenient way of working out time scales as you don't have to do calculations in base 60. In MySQL this is accomplished by the UNIXTIME() function, which can be reversed by using another MySQL function called FROM_UNIXTIME().

However, you can sometimes be left with timestamps in your code and the task of trying to figure out what to do with them.

The first problem is trying to convert a timestamp into a date. So here is a PHP function that does this.

function timestamp($t = null){
 if($t == null){
  $t = time();
 }
 return date('Y-m-d H:i:s', $t);
}

And if you ever have a the opposite problem then here is a PHP function that converts a date string into a timestamp. At the moment the string needs to be in the format YYYY-MM-DD HH:MM:SS, which is what the previous function produced. This isn't too difficult to change, just alter the parameters and order of the explode(' ', $str).

function convert_datetime($str) {
 
 list($date, $time) = explode(' ', $str);
 list($year, $month, $day) = explode('-', $date);
 list($hour, $minute, $second) = explode(':', $time);
 
 $timestamp = mktime($hour, $minute, $second, $month, $day, $year);
 
 return $timestamp;
}

Here is an example of the functions in use.

echo timestamp(convert_datetime('2008-05-10 20:56:00')). '  '. convert_datetime('2008-05-10 20:56:00') . ' 1210467360';

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