adding military time in string representation - php

So what I am trying to do is add two strings together in the form of military time. Here is the example.
Time1 = "01:00";
Time2 = "04:30";
Adding the two together would produce "05:30". This seems incredibly simple, but it has been a long long day for a new learner. Any help would be greatly appreciated.

You can do something like this in PHP 5.3:
$d = new DateTime("01:00");
$f = $d->add(new DateInterval("PT04H30M"));
echo $f->format("H:i"); //outputs 05:30
Converting 04:30 to PT04H30M should be trivial. Note that whether this is actually what you want depends on what you mean by "04:30". This code may or may not sum 4*60+30 minutes to the actual time.
If you mean "4 hours and 30 minutes on the clock" this is always correct. However, if you mean "4*60+30 minutes", it depends on the day and timezone. Example:
$d = new DateTime("2010-03-28 01:00 Europe/Lisbon");
$f = $d->setTimestamp($d->getTimestamp() + (4*60+30)*60);
echo $f->format("H:i"); //outputs 06:30 due to DST
An alternate implementation of the last case (assuming current day and default timezone) for PHP 5.2 is
echo date("H:i", strtotime("+4 hours +30 mins", strtotime("01:00")));
For the first case, we must do:
date_default_timezone_set("UTC");
echo date("H:i", strtotime("+4 hours +30 mins", strtotime("01:00")));

Related

PHP - Check if chosen time is at least 5 minutes into the future

In the application that I'm working on, the user must choose a date/time which is at least 5 minutes into the future. For this, I'm trying to implement a check. Below is the code which checks the time difference between the current time and chosen time.
$cur_date = new DateTime();
$cur_date = $cur_date->modify("+1 hours"); //fix the time since its an hour behind
$cur_date = $cur_date->format('m/d/Y g:i A');
$to_time = strtotime($chosen_date);
$from_time = strtotime($cur_date);
echo round(abs($from_time - $to_time) / 60,2). " minute"; //check the time difference
This tells me the time difference from the chosen time and the current time in minutes. So let's say the current time is 09/22/2015 5:53 PM and the chosen time is 09/22/2015 5:41 PM - it will tell me the difference which is 12 minutes.
What I want to know is how I can tell if those 12 minutes are into the future or in the past. I want my application to only proceed if the chosen time is at least 5 minutes into the future.
You're doing too much work. Just use DateTime() to do the date math for you:
// Wrong way to do this. Work with timezones instead
$cur_date = (new DateTime()->modify("+1 hours"));
// Assuming acceptable format for $chosen_date
$to_time = new DateTime($chosen_date);
$diff = $cur_date->diff($to_time);
if ($diff->format('%R') === '-') {
// in the past
}
echo $diff->format('%i') . ' minutes';
Demo
$enteredDate = new DateTime($chosen_date)->getTimestamp();
$now = new DateTime()->getTimestamp();
if(($enteredDate-$now)/60 >=5)echo 'ok';
Basically, the code takes the two dates converted in seconds since 1/1/1970. We calculate the difference between the two dates and divide the result by 60 as we want minutes. If there is a difference of at least 5 minutes, we're ok. If the number is negative, then we are in the past.
If anyone is looking to do something similar, I found the Carbon library which is included by default with the framework I am using (Laravel 5), it was much easier to do this calculation.
$chosen_date = new Carbon($chosen_date, 'Europe/London');
$whitelist_date = Carbon::now('Europe/London');
$whitelist_date->addMinutes(10);
echo "Chosen date must be after this date: ".$whitelist_date ."</br>";
echo "Chosen Date: ".$chosen_date ."</br>";
if ($chosen_date->gt($whitelist_date)) {
echo "proceed";
} else {
echo "dont proceed";
}

PHP adding exact weekdays to a timestamp

I want to add an x number of week days (e.g. 48 weekday hours) to the current timestamp. I am trying to do this using the following
echo (strtotime('2 weekdays');
However, this doesn't seem to take me an exact 48 hours ahead in time. For example, inputting the current server time of Tuesday 18/03/2014 10:47 returns Thursday 20/03/2014 00:00. using the following function:
echo (strtotime('2 weekdays')-mktime())/86400;
It can tell that it's returning only 1.3 weekdays from now.
Why is it doing this? Are there any existing functions which allow an exact amount of weekday hours?
Given you want to preserve the weekdays functionality and not loose the hours, minutes and seconds, you could do this:
$now = new DateTime();
$hms = new DateInterval(
'PT'.$now->format('H').'H'.
$now->format('i').'M'.
$now->format('s').'S'.
);
$date = new DateTime('2 weekdays');
$date->add($hms);//add hours here again
The reason why weekday doesn't add the hours is because, if you add 1 weekday at any point in time on a monday, the next weekday has to be tuesday.
The hour simply does not matter. Say your date is 2014-01-02 12:12:12, and you want the next weekday, that day starts at 2014-01-03 00:00:00, so that's what you get.
My last solution works though, and here's how: I use the $now instance of DateTime, and its format method to construct a DateInterval format string, to be passed to the constructor. An interval format is quite easy: it starts with P, for period, then a digit and a char to indicate what that digit represents: 1Y for 1 Year, and 2D for 2 Days.
However, we're only interested in hours, minutes and seconds. Actual time, which is indicated using a T in the interval format string, hence we start the string with PT (Period Time).
Using the format specifiers H, i and s, we construct an interval format that in the case of 12:12:12 looks like this:
$hms = new DateInterval(
'PT12H12M12S'
);
Then, it's a simple matter of calling the DateTime::add method to add the hours, minutes and seconds to our date + weekdays:
$weekdays = new DateTime('6 weekdays');
$weekdays->add($hms);
echo $weekdays->format('Y-m-d H:i:s'), PHP_EOL;
And you're there.
Alternatively, you could just use the basic same trick to compute the actual day-difference between your initial date, and that date + x weekdays, and then add that diff to your initial date. It's the same basic principle, but instead of having to create a format like PTXHXMXS, a simple PXD will do.
Working example here
I'd urge you to use the DateInterface classes, as it is more flexible, allows for type-hinting to be used and makes dealing with dates just a whole lot easier for all of us. Besides, it's not too different from your current code:
$today = new DateTime;
$tomorrow = new DateTime('tomorrow');
$dayAfter = new DateTime('2 days');
In fact, it's a lot easier if you want to do frequent date manipulations on a single date:
$date = new DateTime();//or DateTime::createFromFormat('Y-m-d H:i:s', $dateString);
$diff = new DateInterval('P2D');//2 days
$date->add($diff);
echo $date->format('Y-m-d H:i:s'), PHP_EOL, 'is the date + 2 days', PHP_EOL;
$date->sub($diff);
echo $date->format('Y-m-d H:i:s'), PHP_EOL, 'was the original date, now restored';
Easy, once you've spent some time browsing through the docs
I think I have found a solution. It's primitive but after some quick testing it seems to work.
The function calculates the time passed since midnight of the current day, and adds it onto the date returned by strtotime. Since this could fall into a weekend day, I've checked and added an extra day or two accordingly.
function weekDays($days) {
$tstamp = (strtotime($days.' weekdays') + (time() - strtotime("today")));
if(date('D',$tstamp) == 'Sat') {
$tstamp = $tstamp + 86400*2;
}
elseif(date('D',$tstamp) == 'Sun') {
$tstamp = $tstamp + 86400;
}
return $tstamp;
}
Function strtotime('2 weekdays') seems to add 2 weekdays to the current date without the time.
If you want to add 48 hours why not adding 2*24*60*60 to mktime()?
echo(date('Y-m-d', mktime()+2*24*60*60));
The currently accepted solution works, but it will fail when you want to add weekdays to a timestamp that is not now. Here's a simpler snippet that will work for any given point in time:
$start = new DateTime('2021-09-29 15:12:10');
$start->add(date_interval_create_from_date_string('+ 3 weekdays'));
echo $start->format('Y-m-d H:i:s'); // 2021-10-04 15:12:10
Note that this will also work for a negative amount of weekdays:
$start = new DateTime('2021-09-29 15:12:10');
$start->add(date_interval_create_from_date_string('- 3 weekdays'));
echo $start->format('Y-m-d H:i:s'); // 2021-09-24 15:12:10

PHP - Exclude all non-business hours / days from time difference

I have a table which shows the time since a job was raised.
// These are unix epoch times...
$raised = 1360947684;
$now = 1361192598;
$difference = 244914;
$difference needs to exclude any time outside of business hours (ex, 9-5 and weekends).
How could I tackle this?
The thing you have to do are 3 in numbers.
You take your start date and calculate the rest time on this day (if it is a business day)
You take your end date and calulate the time on this day and
you take the days in between and multiply them with your business hours (just those, that are business days)
And with that you are done.
Find a little class attached, which does those things. Be aware that there is no error handling, time zone settings, daylight saving time, ...
input:
start date
end date
output:
difference time in seconds
adjustable constants:
Business hours
Days that are not business days
Very bad idea, but I had no choice because I'm on php 5.2
<?php
date_default_timezone_set('Asia/Seoul');
$start = 1611564957;
$end = 1611670000;
$res = 0;
for($i = $start; $i<$end; $i++){
$h = date("H", $i);
if($h >= 9 && $h < 18){
//echo date("Y-m-d H:i:s", $i) . "<br>";
$res = $res + 1;
}
}
echo $res;
Use DateTime.
Using UNIX time for this is slightly absurd, and you would have to literally remake DateTime.
Look up relative formats where you can specify the hour on the day, e.g.
$date = new DateTime($raised);
$business_start = new DateTime("09:00"); // 9am today
$business_end = new DateTime("17:00"); // 5pm today
The rest is for you to work out.
Oh, and instead of start/end, you could probably use DateInterval with a value of P8H ("period 8 hours")
The problem with using timestamps directly is that you are assigning a context to a counter of seconds. You have to work backwards from the times you want to exclude and work out their timestamps beforehand. You might want to try redesigning your storage of when a job is raised. Maybe set an expiry time for it instead?

Determining elapsed time

I have two times in PHP and I would like to determine the elapsed hours and minutes. For instance:
8:30 to 10:00 would be 1:30
A solution might be to use strtotime to convert your dates/times to timestamps :
$first_str = '8:30';
$first_ts = strtotime($first_str);
$second_str = '10:00';
$second_ts = strtotime($second_str);
And, then, do the difference :
$difference_seconds = abs($second_ts - $first_ts);
And get the result in minutes or hours :
$difference_minutes = $difference_seconds / 60;
$difference_hours = $difference_minutes / 60;
var_dump($difference_minutes, $difference_hours);
You'll get :
int 90
float 1.5
What you now have to find out is how to display that ;-)
(edit after thinking a bit more)
A possibility to display the difference might be using the date function ; something like this should do :
date_default_timezone_set('UTC');
$date = date('H:i', $difference_seconds);
var_dump($date);
And I'm getting :
string '01:30' (length=5)
Note that, on my system, I had to use date_default_timezone_set to set the timezone to UTC -- else, I was getting "02:30", instead of "01:30" -- probably because I'm in France, and FR is the locale of my system...
You can use the answer to this question to convert your times to integer values, then do the subtraction. From there you'll want to convert that result to units-hours-minutes, but that shouldn't be too hard.
Use php timestamp for the job :
echo date("H:i:s", ($end_timestamp - $start_timestamp));
$d1=date_create()->setTime(8, 30);
$d2=date_create()->setTime(10, 00);
echo $d1->diff($d2)->format("%H:%i:%s");
The above uses the new(ish) DateTime and DateInterval classes. The major advantages of these classes are that dates outside the Unix epoch are no longer a problem and daylight savings time, leap years and various other time oddities are handled.
$time1='08:30';
$time2='10:00';
list($h1,$m1) = explode(':', $time1);
list($h2,$m2) = explode(':', $time2);
$time_diff = abs(($h1*60+$m1)-($h2*60+$m2));
$time_diff = floor($time_diff/60).':'.floor($time_diff%60);
echo $time_diff;

PHP Time after midnight problem

I have an array of times I want to print out. I want the times that have passed lets say 12:00 clock to be 'greyed out'.
$theTime = '12:00';
if($theTime >= $time[$i])
{....}
02:30
03:50
03:20
04:50
05:45
19:45
20:00
20:50
20:55
21:25
21:30
22:00
22:45
23:55
00:50
00:55
Im doing a simple compare 12:00 a clock to each value.
The problem occurs when you change the time to after midnight for example 00:15. How can I calculate and print the list in order, when time has passed midnight?
if you pass midnight, more than one day is involved. this means that you have to include the information of day! what day is it? so in order to achieve what you want you should list/store more than just the time! if you store a datetime value, you will have no problems calculating time differences, since php will know in what order to put the times according to the day information.
for that look at the php datetime functions.
they will also help you to calculate differences!
Use unix timestamps. create a unix time stamp for midnight, and then compare all of the others to that. Then format it as a time when you print it out.
(A while since I used PHP, so can't remember quite how to do it, but should be simple. I know I have done something similar before. Take a look at http://php.net/time, http://php.net/manual/en/function.mktime.php and http://php.net/manual/en/function.date.php. Should be simple enough =)
As Svish said, you should use real timestamps, and you should also check the date change... here the, I think, more quick and easy way to know difference between 2 time (and date) :
<?php
$dateDiff = $date1 - $date2;
$fullDays = floor($dateDiff/(60*60*24));
$fullHours = floor(($dateDiff-($fullDays*60*60*24))/(60*60));
$fullMinutes = floor(($dateDiff-($fullDays*60*60*24)-($fullHours*60*60))/60);
echo "Differernce is $fullDays days, $fullHours hours and $fullMinutes minutes.";
?>
note the $date1 and $date2 have to be in mktime format, as :
int mktime ([ int $hour=date("H") [, int $minute=date("i") [, int $second=date("s") [, int $month=date("n") [, int $day=date("j") [, int $year=date("Y") [, int $is_dst=-1 ]]]]]]] )
I solved this problem as follows. It is not the best solution but at least it works:
$before_midnight = strtotime("23:59:59");
$before_midnight++; // this makes exact midnight
$start = strtotime("21:00");
$target = strtotime("03:00");
$after_midnight = strtotime("00:00");
for($i=$start; $i<$before_midnight; $i += 3600)
echo date("H:i", $i). "<br>";
for($i=$after_midnight; $i<=$target; $i += 3600)
echo date("H:i", $i). "<br>";
You have a string ('12:00') and are trying to compare it like a number.
http://us3.php.net/manual/en/language.operators.comparison.php
Like Svish and Paul said, you need to use integer timestamps.
$now = time(); // Get the current timestamp
$timestamps= array(strtotime('midnight'),
strtotime('07:45'),
...
);
foreach ( $timestampsas $time ) {
if ( $time >= $now ) {
// $time is now or in the future
} else {
// $time is in the past
}
}
You can format the timestamps with the date function.
Re. Svish's suggestion - strtotime() is handy for easily creating Unix timestamps relative to the current time, or any arbitrary time.
e.g. strtotime('midnight') will give you the unix timestamp for the most recent midnight.

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