Adding up form variables

[AshleyH]

I have a form which has a selection of checkboxes on. Each checkbox obviously has it's own numeric value.

I have found a way to submit the form and add up the values to give me a total but it seems like there should be a more efficient way of doing it.

At the moment I pass the form value to addup.php which has this code:

<?php
$item1 = $_GET['item1'];
$item2 = $_GET['item2'];
$item3 =$_GET['item3'];
$total = $item1 + $item2 + $item2;
?>

What I'm struggling with is...there are a lot of checkboxes on the form which people may select which means this script would be quite long with a to accommodated each checkbox.

The other element I'm struggling with is if somebody doesn't need 'item2' and only selects 'item1' and 'item2' - will I need to use an if/else statement here?

As I'm sure you can gather I'm a newbie with php so any help appreciated.

Many thanks

[ScallioXTX]

Are you also interested in which checkboxes are checked, or only how many checkboxes are checked?

[AshleyH]

It will be which ones are checked.

[Ren]

If you give all the checkboxes the same name, item[], it will create an array of the values when submitted.

Then working out the sum is...

$total = array_sum($_GET['item']); 

[AshleyH]

We do need to know what items have been passed through - it's a list where people select the items they want to order and an email is sent through with a list of items.

Many thanks

[Ren]

We do need to know what items have been passed through - it's a list where people select the items they want to order and an email is sent through with a list of items.

Many thanks

Ah, K.

So name them, item[0], item[1], ... item[n]

the array_sum() will still work, and can still check if an item has been checked by isset($_GET['item'][$i]))

[AshleyH]

Thanks for coming back to me again.

Being an ultra newbie - is there anyway you could give me an example of how I would use the array_sum() and the isset?

Many thanks

[Ren]

Thanks for coming back to me again.

Being an ultra newbie - is there anyway you could give me an example of how I would use the array_sum() and the isset?

Many thanks

array_sum($_GET['item']) 

Will return the sum of all the checked items.

[AshleyH]

I'm getting an error:

array_sum() [function.array-sum]: The argument should be an array in...

Sorry, like I say - I'm a complete newbie to php.

[Ren]

Hmm.

Does

$total = array_sum($_POST[''item']) 

work?

If the HTML form containing the checkboxes, has an attribute method with value of "POST", then using $_POST instead of $_GET would be correct.

[JAY6390]

Code above should read

$total = array_sum($_POST['item']); 

(note the double apostrophe error)

[allspiritseve]

I'm getting an error:

array_sum() [function.array-sum]: The argument should be an array in...

Sorry, like I say - I'm a complete newbie to php.

Can you show us what your HTML code looks like for the checkboxes?

[AshleyH]

Checkboxes on the form:

<input name="ROSE" type="checkbox" id="ROSE" value="120" />
<input name="RED" type="checkbox" id="RED" value="110" />
<input name="WHITE" type="checkbox" id="WHITE" value="110" />

The next page is where we need to add these form fields up.

It's the next page where I need to take all the check boxes that a user has selected and add up to give me the $total.

But I'm struggling with the part that checks to see which checkboxes have been passed.

Clients can select 'rose', 'red' or 'rose' or any combination of them.

Thanks for reading!

[Jake Arkinstall]

<input name="item[rose]" type="checkbox" id="ROSE" value="120" />
<input name="item[red]" type="checkbox" id="RED" value="110" />
<input name="item[white]" type="checkbox" id="WHITE" value="110" /> 

Then you can use the above to get the sum - if all are checked in the above, it will return 340.

[TomB]

By adding those up you'll have no way to know which ones were checked (you'll only have the total)

You may be better off using bit flags for the values, e.g.

<input name="item[rose]" type="checkbox" id="ROSE" value="1" />
<input name="item[red]" type="checkbox" id="RED" value="2" />
<input name="item[white]" type="checkbox" id="WHITE" value="4" /> 

Then add them up:

$total = 0;
foreach ($_POST['items'] as $value) {
    $total |= $value;
} 

Now you can do:

//Was rose checked?
if (1 & $total) {
//...
}

//were both red and white checked?
if (6 & $total) { 
//..
}

//were all 3 checked?
if (7 & $total) {
//..
} 

It also provides a convenient way to store the selection in a single database field.