Wordpress, php. Using substr() on more variables creates conflict - php

Question

I'm using 2 variables: check-in, check-out
Their format is: dd/mm/yyyy
I want separate the day, month and year into single variables,
in order to compare the integers of:
dd(check-in) with dd(check-out),
mm(check-in) with mm(check-out), and
aaaa(check-in) with aaaa(check-out),
so that the check-in cannot be done after the check-out, and an error appears when somebody try.
On the php file:
$in_date = $_POST['check-in'];
settype( $in_date, "string");
$in_yyyy = substr( $in_date , 6, 4);
settype( $in_yyyy, "integer");
$in_mm = substr( $in_date , 3, 2);
settype( $in_mm, "integer");
$in_dd = substr( $in_date , 0, 2);
settype( $in_dd, "integer");
$out_date = $_POST['check-out'];
settype( $out_date, "string");
$out_yyyy = substr( $out_date , 6, 4);
settype( $out_yyyy, "integer");
$out_mm = substr( $out_date , 3, 2);
settype( $out_mm, "integer");
$out_dd = substr( $out_date , 0, 2);
settype( $out_dd, "integer");
Suppose I typed in input:
check-in: 16/12/2016
check-out: 23/01/2017
However, those are the values the variables takes on:
$in_date = 16/12/2016
$in_yyyy = 2017 // THAT'S WRONG
$in_mm = 01 // THAT'S WRONG
$in_dd =23 // THAT'S WRONG
$out_date = 23/01/2017
$out_yyyy = 2017
$out_mm = 01
$out_dd =23
The problem seems to be caused by "substr". It seems to take on, no matter what, always the last value attributed to it.
Any suggestion?

Answer 1

Assuming you always get the date in the below format, you can use the explode() function in PHP to separate the day, month and year from the date.
$date = '16/12/2016';
$parts = explode('/', '', $date);
$day = $parts[0];
$month = $parts[1];
$year = $parts[2];
unset($parts); // clean up
Your code may look something similar to:
$dates = array(
'check_in' => $_POST['check_in'],
'check_out' => $_POST['check_out']
);
foreach($dates as $_date)
{
settype( $_date, "string");
$parts = explode('/', '', $_date);
$day = $parts[0];
$month = $parts[1];
$year = $parts[2];
settype( $day, "integer");
settype( $month, "integer");
settype( $year, "integer");
}
unset($_date); // clean up

Answer 2

I would strongly recommend that you utilize it with Datetime object when you are working with date/time although explode() or substr() will also work.
$dt = DateTime::createFromFormat('d/m/Y', '16/12/2016');
echo "Year: " . intval($dt->format('Y')) . "\n";
echo "Month: " . intval($dt->format('m')) . "\n";
echo "Day: " . intval($dt->format('d')) . "\n";
Benefit of it is that also you can use this datetime objects to compare your check-in and check-out way easier, or you can even easily calculate nights etc. Try following code:
<?php
$dt = DateTime::createFromFormat('d/m/Y', '16/12/2016');
echo "Year: " . intval($dt->format('Y')) . "\n";
echo "Month: " . intval($dt->format('m')) . "\n";
echo "Day: " . intval($dt->format('d')) . "\n";
$dt_out = DateTime::createFromFormat('d/m/Y', '10/12/2016');
if ($dt > $dt_out) {
echo "Check-in cannot be after check-out\n";
}
$dt_out = DateTime::createFromFormat('d/m/Y', '18/12/2016');
if ($dt < $dt_out) {
echo "This is good!\n";
}
echo "Nights: " . $dt->diff($dt_out)->format("%a") . "\n";