link that delete the item from the cart

[cedtech23]

I am trying to create a third column in my simple shopping cart that will delete the item from the cart. I tried the line below to achieve this feature:

echo "<td><a href=<?=$SERVER['PHP_SELF']?> value=<?php unset($SESSION['cart'][$n])?>>Delete</a></td>";

I received an parse error from php. I don't even know if I am on the right track. Can someone help me out?? I need to know if this link will work and if so why am I getting an error related to this line.

The objective is to have the user click on this link. which will then delete the item from the shopping cart and return the user back to the shopping cart.

This is one of my final projects and I am lost.

here is the enter script below:

<?php
session_start();
if(!isset($SESSION['cart'])){
$SESSION['cart']=array();
}

$products=array('IBM Laptop', 'Dell Laptop', 'Gateway Desktop', 'Service Contract');
$prices=array(200.00, 300.00, 400.00, 199.99);

echo "<table cellspacing=20 >";
echo "<tr><th>Item Title</th><TH>Price</th></tr>";

for($n=0;$n<count($SESSION['cart']);$n++){
echo "<tr>";
echo "<td>".$products[$SESSION['cart'][$n]]."</td>";

echo "<td>".number_format($prices[$_SESSION['cart'][$n]],2)."</td>";

echo "<td><a href=<?=$SERVER['PHP_SELF']?> value=<?php unset($SESSION['cart'][$n])?>>Delete</a></td>";
echo "</tr>";
$total = $total + $prices[$_SESSION['cart'][$n]];
}

echo "<td><b>TOTAL</td></b>";
echo "<td>".number_format($total,2)."</td>";
echo "<td><a href=store.php>Continue Shopping</a></td>";
echo "</table>";

?>

[cedtech23]

I decideed to send a query string to the same page I used the line below.

echo "<td><a href=cart.php?$del=".$_SESSION['cart'][$n].">Delete</a></td>";

I am still lost on the syntax to delete a specific value in an array. Anyone have a clue?? or an idea as it relates to my issues

[aaron_karp]

echo "<td><a href=<?=$SERVER['PHP_SELF']?> value=<?php unset($SESSION['cart'][$n])?>>Delete</a></td>";

To get rid of the parse errors, try formatting the string as a concatenation:

echo "<td><a href=" . <?=$_SERVER['PHP_SELF']?> . "?delete=" . <?=$_SESSION['cart'][$n] ?> . ">Delete</a></td>";

You have the function right, though. Unset() will clear that element from an array. But instead of putting it inside your link tag, you need to remember that PHP is a server-side language, and that it's only going to do stuff for you if you send information to the server.

Therefore, at the top of your page, you need some code like this:

if ($_GET['delete']) { // Test for variable named delete in query string
  unset($_SESSION['cart'][$_GET['delete']]);
}

If you're serious about writing a shopping cart you'll want some error checking in there, but that's a whole other story.

Hope this helps. If not, let me know! 🙂

[cedtech23]

I made the following changes to the script: I added

echo "<td><a href=" . <?=$SERVER['PHP_SELF']?> . "?delete=" . <?=$SESSION['cart'][$n] ?> . ">Delete</a></td>";

this send the user back to the same page and add a vaule in the $_GET['delete'] arrary.

Then I added to the top of the script

if ($GET['delete']) { // Test for variable named delete in query string
unset($SESSION['cart'][$_GET['delete']]);
}

This is suppose to delete that specific value from the array thus deleting it from the cart.

It seems to work the first time then it does not work when I try to delete other items.

here is a link to the cart:

http://nucitytech.com/store.php

I am lost I thought that this would delete the item from the cart. Does anyone know what is the problem??

Full Script listed below:

<?php
session_start();
if(!isset($SESSION['cart'])){
$SESSION['cart']=array();
}
if ($GET['delete']) { // Test for variable named delete in query string
unset($SESSION['cart'][$_GET['delete']]);
}

$products=array('IBM Laptop', 'Dell Laptop', 'Gateway Desktop', 'Service Contract');
$prices=array(200.00, 300.00, 400.00, 199.99);

echo "<table cellspacing=20 >";
echo "<tr><th>Item Title</th><TH>Price</th></tr>";

for($n=0;$n<count($SESSION['cart']);$n++){
echo "<tr>";
echo "<td>".$products[$SESSION['cart'][$n]]."</td>";

echo "<td>".number_format($prices[$_SESSION['cart'][$n]],2)."</td>";

echo "<td><a href=" . <?=$SERVER['PHP_SELF']?> . "?delete=" . <?=$SESSION['cart'][$n] ?> . ">Delete</a></td>";

echo "</tr>";
$total = $total + $prices[$_SESSION['cart'][$n]];
}

echo "<td><b>TOTAL</td></b>";
echo "<td>".number_format($total,2)."</td>";
echo "<td><a href=store.php>Continue Shopping</a></td>";
echo "</table>";

?>

[aaron_karp]

It might help to use the function print_r to see what's contained in your cart array, both before and after running the delete thing.

By the way, I have a better way for you to structure your cart program. Think about doing it like this:

$_SESSION['cart'] = array

$_SESSION['cart'][product ID] = quantity in cart

Therefore if someone has 3 IBM Laptops (product ID 0) and 7 Gateway Desktops (product ID 2) in their cart, the array would look like this:

$SESSION['cart'][0] == 3
$SESSION['cart'][2] == 7

Then, to generate your table:

foreach($_SESSION['cart'] as $product => $quantity) {
  echo "<tr>
               <td>" . $products[$product] . "</td>
               <td>" . $quantity . "</td>
               <td><a href=cart.php?delete_id=$product>Delete</a></td>
             </tr>";
}

And to process deletes:

if ($_GET['delete_id']) {
  unset($_SESSION['cart'][$_GET['delete_id']]);
}

How's that look?

[cedtech23]

I don't understand

$_SESSION['cart'] = array

$_SESSION['cart'][product ID] = quantity in cart

please explain does that mean create to arrays is that the correct syntax

I am also lost here

foreach($_SESSION['cart'] as $product => $quantity) {
echo "<tr>
<td>" . $products[$product] . "</td>
<td>" . $quantity . "</td>
<td><a href=cart.php?delete_id=$product>Delete</a></td>
</tr>";
}

Originally posted by aaron_karp
It might help to use the function print_r to see what's contained in your cart array, both before and after running the delete thing.

By the way, I have a better way for you to structure your cart program. Think about doing it like this:

$_SESSION['cart'] = array

$_SESSION['cart'][product ID] = quantity in cart

Therefore if someone has 3 IBM Laptops (product ID 0) and 7 Gateway Desktops (product ID 2) in their cart, the array would look like this:

$SESSION['cart'][0] == 3
$SESSION['cart'][2] == 7

Then, to generate your table:

foreach($_SESSION['cart'] as $product => $quantity) {
  echo "<tr>
               <td>" . $products[$product] . "</td>
               <td>" . $quantity . "</td>
               <td><a href=cart.php?delete_id=$product>Delete</a></td>
             </tr>";
}

And to process deletes:

if ($_GET['delete_id']) {
  unset($_SESSION['cart'][$_GET['delete_id']]);
}

How's that look? [/B]

[aaron_karp]

Sorry for any confusion. That isn't the syntax, I was just trying to describe an alternate way of doing it. What I meant to say is that $_SESSION['cart'] is an array, right? So you can store vales in its indicies.

if you write: $_SESSION['cart'][23] = "hello";

then the value of $_SESSION['cart'][23] is going to be "hello". It doesn't matter if elements 0-22 haven't been set. Of course, instead of "hello," you can set it to a number.

My recommendation is as follows: You have a unique ID for each product, correct? So, set the value of $_SESSION['cart'][the unique id for that product] equal to the quantity of that product in the cart. If someone has three Dell Computers in their cart, and Dell computers have a product ID of 7, then the following is true:

$_SESSION['cart'][7] == 3

Make sense? It's an easy way to keep track of both the products in the cart as well as the quantities.

If you want to add another item to the cart, you would use the following code. For example we'll use refrigerator magnets, which we'll say have an ID of 19. Let's put 5 in the cart.

$_SESSION['cart'][19] = 5;

// Then to add another item:

$_SESSION['cart'][19]++;

See how it works? It's a better way to organize your cart than what you're doing.

Summary:
$_SESSION['cart'][p] == q

p is product ID
q is quantity of product (whose product ID is p) in cart

If you understand that, then the other code should make sense as well.

[cedtech23]

I understand the concept but I am lost on how would I translate that to my code:

example

I have four product

IBM Laptop

Dell Laptop

Gateway Laptop

Service Contract

does those represent the product id

and what about the prices where do they come into play.

would I create a session for every product.

[aaron_karp]

Well, if you were building a realistic shopping cart you would be storing your product and pricing data in a database. But since it looks like you are doing a smaller project, we can store them in arrays...

$products = array(
0 => 'Dell Computer',
1 => 'Gateway',
2 => 'Other');

$prices = array(
0 => 600,
1 => 550,
2 => 450);

Then if you cart looked like this:

$_SESSION['cart'][1] = 3

Then we just added 3 gateways to the cart.

When you want to list out the items:

foreach ($_SESSION['cart'] as $product => $quantity) {
  // loops through each item in cart
  // temp. stores the product ID (aka the index in the $products array) in the variable named $product
  // temp. stores the quantity of that product as $quantity
  $price = $prices[$product];
  $total_price_for_product = $price * $quantity;
  // echo out those variable however you want to.

}