Incrementing array value in PHP Session variable

Question

I have this array in PHP session, which I want to step through one step at a time.

How do I get the current array index and move one step forward or backward? Here's the code:

for ($i = 0; $ < 10; $i++){    
    $result_array[] = $i;   
}

$_SESSION['theValue'] = $result_array;

I tried:

$_SESSION['theValue'] [0]++;

to move the array one step at a time, but it only displays the same value at that index. Is there a way I can keep incrementing the index?

I'm not sure I'm making much sense.

to move the array one step at a time What does this line mean? — Jared Farrish
– Jared Farrish, Commented Oct 23, 2011 at 18:43

Community · Accepted Answer · 2023-11-17 20:08:53Z

4

$_SESSION['theValue'] [0]++ actually increments the first value in the array rather than incrementing the array index. Use the array functions, and especially key and next, to navigate through the array.

Or, if you want to keep the last array index in the session, you may want to store the index as a separate session value. The length of the array is read using count($array). The indexes reach from 0 to count - 1.

edited Nov 17, 2023 at 20:08

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answered Oct 23, 2011 at 18:44

GolezTrol

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Comments

Flipper · Accepted Answer · 2011-10-23 18:42:59Z

3

If I understand your question correctly that you want to loop through the array then you should do something like this:

$size = count($_SESSION['theValue']);
for($i=0; $i < $size; $i++)
{
    $currentValue = $_SESSION['theValue'][$i];
}

Make sure that size is a local variable and you are not using count() directly in the for loop.

Your method of doing $_SESSION['theValue'][0]++ actually increments the value at the zero index.

answered Oct 23, 2011 at 18:42

Flipper

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Comments

Marek Sebera · Accepted Answer · 2011-10-23 19:10:41Z

1

init session array

$_SESSION['theValue'] = $result_array;
$_SESSION['currentIndex'] = 0;

create buttons next/previous like this

$prev = $_SESSION['currentIndex'] == 0 ? 0 : $_SESSION['currentIndex'] - 1;
$next = $_SESSION['currentIndex'] == sizeof($_SESSION['theValue']) ? $_SESSION['currentIndex'] : $_SESSION['currentIndex'] + 1;

and on going to next/previous page, simply increment/decrement $_SESSION['currentIndex']

usecase:
So when you create link like this:

<a href="index.php?page=1">Next</a>
<a href="index.php?page=0">Prev</a>

you need to catch the value of $_GET['page'] and save it to currentIndex session property before rendering content.

if(isset($_GET['page'])){
    if(is_numeric($_GET['page']){
        if($_GET['page'] >= 0 && $_GET['page'] <= sizeof($_SESSION['theValue'])){
            $_SESSION['currentIndex'] = $_GET['page'];
        }
    }
}
// place code which works with 'currentIndex' and array in session here...

edited Oct 23, 2011 at 19:10

answered Oct 23, 2011 at 18:44

Marek Sebera

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4 Comments

Helen Neely Over a year ago

Thank you for your code, but I just keep getting 1 and 0 when I press the prev and next. It does not increment more than 1. Any thoughts? Thanks again.

Marek Sebera Over a year ago

and are you saving current value to currentIndex session property? you have to save this variable when page reloads

Helen Neely Over a year ago

Thanks again, but how do I save currentIndex and refer to it? Forgive me question.

Marek Sebera Over a year ago

@HelenNeely I've gave you example to end of my answer.

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