Defining indexes+elements in an associative array

Question

Why does the following code:

if (isset($_GET['trainType']) && isset($_GET['onTime']) && isset($_GET['gotSeat'])) {
    $train[0]['trainType'] = $_GET['trainType'];
    $train[0]['trainType']['onTime'] = $_GET['onTime'];
    $train[0]['trainType']['gotSeat'] = $_GET['gotSeat'];   
    echo '<pre>';
    print_r($train);
    echo '</pre>';
}

Return the following array:

Array
(
    [0] => Array
        (
            [trainType] => tLine
        )

)

I had initially assumed it would return something more resembling to this:

Array
(
    [0] => Array
        (
            [trainType] => 'passenger'
            Array =>
                (
                    [onTime] => true
                    [gotSeat] => true
                )

        )

)

Any guidance on what I should do to achieve what I am trying to do? I am hoping that my code makes what I am trying to do obvious.

trainType = string 'VLine' (length=5) onTime = string 'true' (length=4) gotSeat = string 'true' (length=4) — anditpainsme
– anditpainsme, Commented Oct 23, 2012 at 5:35
so you are trying to append to a string as though it were an array — benedict_w
– benedict_w, Commented Oct 23, 2012 at 5:36

noetix · Accepted Answer · 2012-10-23 06:06:20Z

1

This line will set trainType to a string value:

$train[0]['trainType'] = 'hello';

Then these lines will actually be used for character substitution, with a slight twist:

$train[0]['trainType']['onTime'] = 'foo';
$train[0]['trainType']['gotSeat'] = 'bar';

Both onTime and gotSeat will result in 0 (because you're working with a string) and will replace the first character with f then b.

Therefore print_r($train) returns:

(
    [0] => Array
        (
            [trainType] => bello
        )

)

Here is how I would format this data:

// define our list of trains
$train = array();

// create a new train
$new = new stdClass;
$new->type = 'a';
$new->onTime = 'b';
$new->gotSeat = 'c';

// add the new train to our list
$train[] = $new;

The result of print_r($trains):

Array
(
    [0] => stdClass Object
        (
            [type] => a
            [onTime] => b
            [gotSeat] => c
        )

)

Accessing this data:

echo $trains[0]->type; // returns 'a'
echo $trains[0]->onTime; // returns 'b'
echo $trains[0]->gotSeat; // returns 'c'

edited Oct 23, 2012 at 6:06

answered Oct 23, 2012 at 5:39

noetix

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2 Comments

anditpainsme Over a year ago

That is pretty cool. I've never really worked with objects before, but this is probably what I should have been doing. Even though I could have originally done this w/ my original array, this answer has given me an idea which will improve my code in the long run so I appreciate that. One question I had however is why the contents of the array was mixed instead of ignored, like you said? (ie: VLine became TLine (replaced the first letter of VLine with the T from True (from the other $_GET vars)

noetix Over a year ago

I've updated my answer to solve this problem. It wasn't immediately clear until I ran a test locally.

Stefan · Accepted Answer · 2012-10-23 06:20:03Z

0

You are implicitly setting (or needing) a key = 0 for

array (
  "onTime" => true,
  "gotSeat" => true
)

So you must instead just do this:

if (isset($_GET['trainType']) && isset($_GET['onTime']) && isset($_GET['gotSeat'])) {
    $train[0]['trainType'] = $_GET['trainType'];
    $train[0][0]['onTime'] = $_GET['onTime'];
    $train[0][0]['gotSeat'] = $_GET['gotSeat'];
    echo '<pre>';
    print_r($train);
    echo '</pre>';
}

Note that all I did was to change the incorrect $train[0]['trainType']['onTime'] to $train[0][0]['trainType'] in your code, and similarly for gotSeat.

Or you can define a new key, maybe like this: $train[0]['booking']['onTime'] = ...

edited Oct 23, 2012 at 6:20

answered Oct 23, 2012 at 6:07

Stefan

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