associative

[Anon]

hi,

is it possible to detect whether an array is associative or not ? i.e. was the array defined with key/value-pairs or only with values.

example:
$a = array("one", "two", "three");
$b = array("a"=>"one", "b"=>"two", "c"=>"three");
$c = array("1"=>"one", "2"=>"two", "3"=>"three");

to test whether the key is a number, doesn't work,of course.

thanx a lot
joe

[polson]

This is a quick hack but should work (note: does not take into acount types, such as strings and integers), here goes :

<?php

// Test it with the function below
if ( isAssociative($c) ) {

print 'this is associative';

} else {

print 'this is not associative';

}

function isAssociative($array)
{

// Get the keys from our array
$keys = array_keys($array);

foreach ($keys as $key => $value) {

// If our new keys equal our old keys then
// it's associative else if just one key
// is out of place then it is not.
if ($key != $value) {

        Return FALSE;
        break;

    } else {

        Return TRUE;
    }
}

}

?>

[inter_joe]

that's a good idea, but two things:
- i think you mixed up the if-clause
(If our new keys equal our old keys then it's not associative, and vice versa)
- the foreach-loop only tests the first key

so i think your function is identical to this one:
function isAssociative($array)
{
return (key($array) == "0") ? FALSE : TRUE;
}

to test each key you could use something like:

function isAssociative($array)
{
$keys = array_keys($array);
$ass = TRUE;

foreach ($keys as $key => $value) {
if (strcmp($key, $value) == 0) $ass = FALSE;
}
return $ass;
}

but these functions fail for:
$c = array("0" => "a", "1" => "b");
or
$c = array(0 => "a", 1 => "1");

but i think, it's the best you can do. i have no other idea.

thanx a lot
joe

[polson]

Ahh, that makes sense. Just tested my function and it does indeed have issues :-)