How do I make nested php arrays work in html attributes?

Question

I'm trying to use a nested php array grabbed from a database in a loop to create a bunch of html elements.

Below is a cleaned up section of that code which still contains the strange error: non-nested arrays can be used properly, as in the code below:

   <?php
        $array = array();
        $array[] = "a";
        $array[] = "b";
        $array[] = "c";
        $x = 1;

        echo "<input type='radio' value=\" $array[$x] \" id='$x'> <label for=\" $array[$x] \">" . $array[$x] . "</label><br>";
    ?>

But not when the array is nested, as here:

    <?php
        $subarray = array();
        $subarray[] = "a";
        $subarray[] = "b";
        $subarray[] = "c";
        $array = array();
        $array[] = $subarray;
        $subarray[] = "p";
        $subarray[] = "q";
        $subarray[] = "r";
        $array[] = $subarray;
        $x = 1;
        echo "<input type='radio' value=\" $array[$x][$] \" id='$x'> <label for=\" $array[$x][1] \">" . $array[$x][1] . "</label><br>";
    ?>

For some strange reason, the "$array[$x][$x]" and "$array[$x][1]" only work outside of the "<>"-tags and brings about the "b" stored in the array at [1][1]. But within the "<>"-tags they only show as "Array[1]" in the inspector. The "$x" works fine within the "<>"-tags.

What can I do to make this work?

Thanks!

Marc B · Accepted Answer · 2014-06-26 15:02:25Z

1

PHP's parser is not "greedy" for arrays:

$foo = array();
$foo[1] = array();
$foo[1][2] = 'bar';

echo "$foo";       // Output: Array
echo "$foo[1]"     // Output: Array
echo "$foo[1][2]"; // Output: Array[2]

For the 2nd and subsequent array "dimensions", you have to use the {} extended syntax:

echo "{$foo[1][2]}"; // Output: bar

Note that when using {} notation, string keys MUST be quoted:

echo "$foo[bar]"; // ok
echo "$foo['bar']"; // causes warning
echo "{$foo['bar']}"; // ok
echo "{$foo[bar]}"; // undefined constant warning

answered Jun 26, 2014 at 15:02

Marc B

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2 Comments

Henrik Over a year ago

Well, isn't that marvelous! Thanks! Why would it do that though?

Marc B Over a year ago

because PHP's internal development consistency is about as appetizing as an unflushed bus stop toilet: none at all.

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