I want to use $_SESSION to store items in cart. The items are defined by id, each item has 3 sizes and for each size there will be stored item's quantity. I would like to use multidimensional associative array like that
$_SESSION['cart']['id'.$_GET['id']]['size'.$_POST['size']]['quantity'] += $_POST['quantity'];
but I guess the problem which I am getting (Notice: Undefined index) is because the arrays are not defined first.
I would like to keep it simple, so what would be the easiest way?
Your issue is that you're just assuming the items are set in $_SESSION. You need to assume they aren't and start by adding them in.
You'd harness isset().
if(!isset($_SESSION['cart']['id'.$_GET['id']])) {
$_SESSION['cart']['id'.$_GET['id']] = array(
'sizeONE' => array(
'quantity' => 0
),
'sizeTWO' => array(
'quantity' => 0
),
'sizeTHREE' => array(
'quantity' => 0
),
);
}
You'd obviously modify the above to probably only set the product id as you require then run through the same sort of isset() to add the selected sizes. I'm just showing you how to create the initial structure array.
I'd argue the best manner to store this data isn't in a multidimensional array, but rather in an Object (and not in $_SESSION, but that's a whole different topic).
If you want to approach this with an object, I'd use a variation of the following:
$myItem = new stdClass;
$myItem->id = $_GET['id'];
$myItem->sizeOne = new stdClass;
$myItem->sizeOne->name = "sizeOne";
$myItem->sizeOne->quantity = 1;
// repeat for sizeTwo and sizeThree
$_SESSION['cart'][$myItem->id] = $myItem;
Benefits:
More of an OOP approach to your program.
Drawbacks:
Storing an Object in the $_SESSION may cause scalability issues.
Related
Ive come upon the following code and having trouble deciphering its use.
(changed up the variable names a bit for simplicity)
$fooo = array(
'dog' => array('pages', 'home'),
'cat' => array('users', 'login'),
'bird' => array('users', 'reset', 1),
);
I am familiar with associative arrays but have not seen this "nested array" implementation before.
Is this code creating an array of arrays?
For example, $fooo['dog'] returns an array where $dog[0]='pages' and $dog[1]='home'
That seems wrong.
Yes, this is an array of arrays. But it perhaps may be more accurate to describe it as an associative array with an indexed array for every value.
The following can be done with it:
$fooo['dog'] // gets array("pages", "home")
$fooo['bird'][0] // gets "users"
$fooo['cat'][1] // gets "login"
$fooo['cow'] = array('x', 'y'); // adds another value to the outer array
$fooo['bird'][] = 2; // $fooo['bird'] now equals array('users', 'reset', 1, 2)
There is nothing wrong with this code, but your example is lacking practicality. There is plenty of code that uses such structures though. For example, a logical representation of a menu with sub-menus on a website (which seems like the source of your sample), this data structure can then be looped to generate an HTML/CSS menu.
Consider the following array of objects:
class Person {
public $name;
public $occupation;
public function __construct($n, $o){
$this->name = $n;
$this->occupation = $o;
}
}
$people = array(
new Person("John", "singer"),
new Person("Paul", "guitar"),
new Person("George", "bass"),
new Person("Ringo", "drums")
);
Is there any quick way to access the objects? I wouldn't mind storing them in a different datatype (as opposed to array) if another datatype could make access easier.
Example of accessing an object: I would like to now change the "Paul" object to have an occupation of singer. This is the current solution:
foreach ( $people as &$p ) {
if ( $p->name=="Paul" )
$p->occupation="singer";
}
Alternatively, I might need to access based on a different property: Let's change all the singers' names to Yoko:
foreach ( $people as &$p ) {
if ( $p->occupation=="singer" )
$p->="Yoko";
}
Another example of accessing an object, this time in order to get the occupation of Ringo:
$ringosOccupation="";
foreach ( $people as $p ) {
if ( $p->name=="Ringo" )
$ringosOccupation = $p->occupation;
}
I suppose that I could write a People class that stores each Person object in an internal array and supplies functions to change or read occupation, but if PHP has anything cleverer build in I would love to know.
Thanks.
Just index your array with the names:
$people = array(
"John" => new Person("John", "singer"),
"Paul" => new Person("Paul", "guitar"),
"George" => new Person("George", "bass"),
"Ringo" => new Person("Ringo", "drums")
);
// Paul is the new drummer:
$people["Paul"]->occupation = "drums";
It creates a little bit of redundancy, but surely that redundancy won't be more memory or compute intensive than looping over all of them to locate the one you need every time you need to modify something.
Update:
After the question was updated, it is clear that names may be non-unique or other properties needed for access. In that case, you might be better off using a database to store object state if you have to do it often. You can't escape needing to iterate over the array if it can't be uniquely indexed. It is trivially easy to make these changes in a database, but you would need to be rebuilding the objects all the time.
So, if your array is not too large, keep looping like you have been. If it meets your performance needs, its an ok method. If you have lots and lots of these to modify, and modify often, I would suggest storing them in a database and building the objects only when you need to read one out. Then you could do:
UPDATE people SET name = 'Yoko' WHERE occupation = 'singer'
Why aren't you just setting the key of the elements to the name?
$people = array(
'john' => new Person("John", "singer"),
'paul' => new Person("Paul", "guitar"),
'george' => new Person("George", "bass"),
'ringo' => new Person("Ringo", "drums"),
);
I am seeking for someone's knowledge out here.
Right now, I would need to merge several arrays into a bigger one, but all of those arrays depend on a function.
This function returns a numeric array containing different quantities of numbers between 1 and 7 :
function Possible($i, $j, $grid)
$possible = Possible($i, $j, $grid)
I'm working with a grid, and the function returns a different array for every case of the grid. What I would like to do is to merge those 7 arrays into another one. Some numbers may be present more than once in this big array, but I want it this way.
I tried using for loops, while loops and some other techniques, but nothing worked. In this case, it is not possible to manually define every array, since they change depending of what is contained in the grid and there are too many. It has to be done automatically, and this is where I get stuck.
for ($jj=0; $j<7; $j++){
$possRow = array_merge( ###what do I add here or what do I change in this code to make everything work###
Thank you if someone can help me out!
Etpi
hope this help:
$biggerOneArray = array();
for($k=0;$k<7;$k++) {
$biggerOneArray[] = Possible($i,$j,$grid);
}
Then you can check your bigger array, may contains all arrays of the iterations of the loop (7 arrays merged).
var_dump($biggerOneArray);
The output should be this:
array(
(int) 0 => array(
'key' => 'value',
'key2' => 'value2'
),
(int) 1 => array(
'key3' => 'value3',
'key4' => 'value4'
)
)
etc...
I'm sorry but your description isn't very clear. But just to get you started you might look at this solution.
function Possible($i, $j, $grid) {
// some code ... e.g. $array[] = "some data";
return $array;
}
By creating a small array for each grid and returning it using return $array you get a few little arrays which you can inturn place into a for loop to merge it into one larger array. However i believe the var $jj must have some meaning in the function it self as well.
for($jj=0;$jj<7;$jj++) {
$merged_array[$jj] = Possible($i,$j,$grid);
}
Maybe if you descripe your problem a little more and post an exmple of the array's your working with i can give you a better answer.
I have a question about associative arrays in php.
I have following array in which there are two items named 4 and 2 respectively.
$items = array(4,2);
Now i want to associate each item's quantity to it which can be done as follows:
$items['4']=23;
$items['2']=0;
which means that there are 23, 'item 4s' and no 'item 2'.
But I sometimes don't know in advance what is there in the $items so i want to associate quantity on basis of location. I wanted to do something like associate 23 to whatever is there on the zero location of the item array:
$items['items[0]']=23;
This of course did not work because its not the right way to extract whatever is placed on the zero location of items. Can anyone please tell me how do i do that?
You are confusing in the use of item and items. I imagine you have both an item array and an items array, else things can easily get hairy.
Anyhow, you just refer to it as a variable, not as a string:
$items[$item[0]] = 23;
Let me get this straight. So you start with an array that looks like this:
$items = array( 0 => 4, 1 => 2 )
And you want to end up with an array that looks like this: ?!
$items = array( 0 => 4, 1 => 2, 2 => 0, 4 => 23 )
I think you should use your array as a kind of "map". The item number is your key, and the quantity your value.
By calling
$items = array(4,2);
you create
$items[0] = 4;
$items[1] = 2;
but you want to use the 4 and 2 as a key in your array. So you should instead use
$items = array( 4 => false, 2 => false );
where false stands for an item that has not yet a quantity associated (could also be e.g. -1).
This creates
$items[2] = false;
$items[4] = false;
When using false, you can check for not assigned values by calling
if ($items[4] === false) {
echo "No quantity set!";
}
And now the second step.. if you want to assign the item #4 a quantity of 23, just call
$items[4] = 23;
So I don't think you will want to rely on the order inside your array..
I'm trying to create an array to display the last 5 products a customer has viewed.
The array is a 2 dimensional array like below...
$RView= array(
array( ID => "1001", RefCode => "Ref_01", Name => "Name_01" ),
...
array( ID => "1005", RefCode => "Ref_05", Name => "Name_05" )
);
The array values are retrieved from the products recordset and is designed to function as follows when a customer visits a product page.
Page will check if a Session Array exists
If yes, an array variable is created from existing Session
If no, a new array is created.
Array will add the new product details.
Array will count if there are more than 5 existing products in the array.
If yes, it will remove the oldest.
If no, moves to next step.
A Session is created/updated from the revised Array.
My current effort is attached below...
Many thanks for any help.
<?php
session_start()
// Get or Create Array
IF (isset($_SESSION['sessRView'])) {
$RView = ($_SESSION['sessRView']); }
ELSE {
$RView = array(array());
}
// Append currently viewed Product to Array
array(array_unshift($RView, $row_rsPrd['PrdID'], $row_rsPrd['RefCode'], $row_rsPrd['Name']));
// Check if more than 5 products exist in Array, if so delete.
IF (sizeof($RView) > 5) {
array(array_pop($RView)); }
// Update Session for next page
$_SESSION['sessRView'] = $RView;
// Display Array
for ($row = 0; $row < 5; $row++)
{
echo "<ul>";
echo "<li><a href='?PrdID=".$RView[$row]["PrdID"]."'>".$RView[$row]["RefCode"]."</a> : ".$RView[$row]["Name"]."</li>";
echo "</ul>";
}
?>
It's more or less right - just 2 lines need to be changed.
There's no need for the extra array() around array_unshift and array_pop.
When you use array_unshift you're pushing an array of items (not the id/codes individually) - I think you mean array_unshift($RView, array($prodid,$name,...))
What if $RView doesn't have 5 elements? In that case you're accessing undefined array indices (which may or may not show an error). Change it to a foreach loop: e.g.
foreach ($Rview as $prod) echo $prod['Name']...
It should work after you make these changes. You might want to clean up the coding style a bit, though :)
EDIT: Oh, I see, when you're referencing the array in the for loop it doesn't know that the array has "ProdID" and "Name" indices. When you make an array you have to define the indexes using the => operator.
Add indexes to the array when you array_unshift:
array_unshift($RView, array("ProdID" => $row_rsProd["ProdID"], "Name"...))
If row_rsProd isn't too big, you can just tack the entire row_rsprod onto $RView.
so change array_unshift(...) to just $RView[] = $row_rsProd
This way the indexes are preserved.
Alternatively you can change the indicies in the for loop to match. Right now the array you unshift onto $RView is 0-based - $RView[0][0] is the product ID for the first product, etc.
So you can change the stuff in the foreach loop to
echo "<li>..." $prod[0] $prod[1] $prod[2]
Hope that helps!