How to calculate price of 1 or more hotel rooms in php using arrays

[webdeveloper123]

Hi Guys,

Been looking at this for a few days now, but not sure how to go about it. I wanted to book 1 or more hotel rooms (depending on user input) but I'm stuck as to how to do it. I have the following code: (only showing relevant parts)

<?php
$reservedrooms = [];

if ($_SERVER['REQUEST_METHOD'] == 'POST') {

$reservedrooms = $_POST['reservedrooms'] ?? '';

$sqlbookquery = "SELECT r.room_id, rs.price FROM room AS r INNER JOIN roomsize AS rs ON r.size_id = rs.size_id;";
$statement1 = $pdo->query($sqlbookquery);
$bookquery  = $statement1->fetchAll();

}

?>

The reservedrooms array contains room_id from a checkbox on the search page. So If the user wanted to book 3 rooms, it will pick up the 3 matching ID's. I have tested this, it is working properly.

Then to book the rooms I was thinking to compare the 2 arrays, and return the matching ID's, along with their price, then multiply that by the number of nights (I already done this part, I get the correct result of nights). It is stored in a variable.

On the comparing arrays, I tried to use array_intersect but I got an error (probably because I was comparing 2 arrays that didn't match up)  E.g the reservedrooms array has only room_id in there and the bookquery has room_id and price. That is just a theory. Is it even like that?

There are several other array functions I was looking at but not sure which one to use. in_array, array_search, array_diff. 

Can someone please give me some help on how to go about this? 

[Barand]

Your data probably looks something like this

$reservedrooms = [2, 4, 6];

$bookquery  = [ 0 => ['room_id' => 2, 
                      'price' => '125'
                      ],
                1 => ['room_id' => 3, 
                      'price' => '125'
                      ],
                2 => ['room_id' => 4, 
                      'price' => '125'
                      ],
                3 => ['room_id' => 5, 
                      'price' => '125'
                      ]
              ];

You can get an array of room ids from $bookquery in same format as $reserved rooms with

$queryrooms = array_column($bookquery, 'room_id')

 

[Barand]

Alternatively

$bookquery = array_filter($bookquery, fn($v)=>in_array($v['room_id'], $reservedrooms));

$totalprice = array_sum(array_column($bookquery, 'price'));

 

[webdeveloper123]

Thanks Barand, I'll give it a go

[webdeveloper123]

Yes! Done it! Thanks Barand

[webdeveloper123]

Hey Barand,

Sorry quick question. I am using the following code:

$bookquery = array_filter($bookquery, fn($v)=>in_array($v['room_id'], $reservedrooms));

$totalprice = array_sum(array_column($bookquery, 'price'));

Works great. But I was trying to find bugs in my app and I thought what If I tried to not select any rooms for booking from the search screen and just press "Book". It gives me this error:

Fatal error: Uncaught TypeError: in_array(): Argument #2 ($haystack) must be of type array, 
string given in /var/www/vhosts/:58 Stack trace: #0 /var/www/vhosts/): in_array() 
#1 [internal function]: {closure}() #2 /var/www/vhosts/: array_filter() 
#3 {main} thrown in /var/www/vhosts booking.php on line 58

Now I read the manual & I've used in_array before and the error is saying the second argument must be array (which in this case would be $reservedrooms) but it's receiving a string instead. So I'm assuming that the blank array is being interpreted as a string. I tried to fix is like this:

if (!$reservedrooms) {
	echo "You must select a room";
}

The echo line shows , but so does the original errror.

Here is my related code:

<?php


$formattedInterval = $difference->format('%d');


 
if (!$reservedrooms) {
	echo "You must select a room";
}

$bookquery = array_filter($bookquery, fn($v)=>in_array($v['room_id'], $reservedrooms));

$totalprice = array_sum(array_column($bookquery, 'price'));

$alltogether = $totalprice * $formattedInterval;

$alltogether  = number_format($alltogether);

?>

Thanks

[Barand]

If you have no reserved rooms, how is $reservedrooms defined in your script;. Are you initially defining it as an empty string

$reservedrooms = "";

or an empty array

$reservedrooms = [];

 

[webdeveloper123]

empty array

$reservedrooms = [];

 

[Barand]

Shouldn't give that error then. It should just give a zero price because none of the booked query room ids are that empty array.

Are you sure it's not being overwritten anywhere?

[webdeveloper123]

Hey Barand,

No it doesn't look like anything is being over written. But I do have a count() statement later on on $reservedrooms so that I can output how many rooms the user has booked. But I can't see how the 2 are linked. Here is my full code:

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Booking</title>
</head>
<body>



<?php

include 'includes/db.php'; 
include 'includes/functions.php'; 


$reservedrooms = [];


$today = new DateTime();


if ($_SERVER['REQUEST_METHOD'] == 'POST') {

$reservedrooms = $_POST['reservedrooms'] ?? '';
$arrivalDate = $_POST['arrivaldate'];
$departureDate = $_POST['departuredate'];

$totaladults = $_POST['numofadults'] ?? '';
$totalchild = $_POST['numofchild'] ?? '';


$arrivalObj = new DateTime($arrivalDate);
$departureObj = new DateTime($departureDate);

$difference = $arrivalObj->diff($departureObj);

$formattedInterval = $difference->format('%d');

$sqlbookquery = "SELECT r.room_id, rs.price FROM room AS r INNER JOIN roomsize AS rs ON r.size_id = rs.size_id;";

$statement1 = $pdo->query($sqlbookquery);
$bookquery  = $statement1->fetchAll();

if (!$reservedrooms) {
} else {
		echo "You must select a room";
}

 
$bookquery = array_filter($bookquery, fn($v)=>in_array($v['room_id'], $reservedrooms));

$totalprice = array_sum(array_column($bookquery, 'price'));

$alltogether = $totalprice * $formattedInterval;

$alltogether  = number_format($alltogether);

if ($formattedInterval == 0) {
   echo "Price for the night is: &pound;$totalprice<br>";

} else {
	echo "Total Price: &pound;$alltogether<br>";

}

if ($arrivalObj == $departureObj) {
	echo "You will be charged for a minimum of 1 night<br>";
} else {
	echo $difference->format('%d nights<br>');
}


if ($totaladults == 1) {
	echo "$totaladults Adult<br>";
} else {
	echo "$totaladults Adults<br>";
}



if ($totalchild == 1) {
	echo "$totalchild Child<br>";
} elseif ($totalchild == 0) {
	echo '';
} else {
	echo "$totalchild Children<br>";
}

 
 $countrooms = count($reservedrooms);

 if ($countrooms == 1) {
 	echo "$countrooms Room";
 } else {
 	echo "$countrooms Rooms";
 }


}

?>



<p>Arrival date is:</p>
<?= htmlspecialchars($arrivalObj->format('D, jS M Y')) ?>
<p>Departure date is:</p>
<?= htmlspecialchars($departureObj->format('D, jS M Y')) ?>




</body>
</html>

Thanks

[dodgeitorelse3]

58 minutes ago, webdeveloper123 said:

$reservedrooms = $_POST['reservedrooms'] ?? '';

 

[webdeveloper123]

Hey dodgeitorelse3,

I changed it to:

$reservedrooms = $_POST['reservedrooms'];

And:

$reservedrooms = $_POST['reservedrooms'] ?? 0;

On both of them, I still get the same error. And on the first one I get an additional error:

Warning: Undefined array key "reservedrooms" in /var/www/vhosts/ booking.php on line 25

Thanks

[webdeveloper123]

Oh I get it. 

$reservedrooms = $_POST['reservedrooms'] ?? '';

Is storing a blank or NULL value If a room is not selected, it is then passing the NULL or blank value to the array function, thus the error message. Is that right?

Edited October 18, 2023 by webdeveloper123

[Barand]

2 minutes ago, webdeveloper123 said:

$reservedrooms = $_POST['reservedrooms'] ?? '';

That is setting $resrved rooms to a string value if not posted. The default needs to be an empty array

$reservedrooms = $_POST['reservedrooms'] ?? [];

 

[webdeveloper123]

Thanks Guys, it's fixed!