Variable variable with arrays

Question

I'm confused in how to use $$ to use a string as a variable, mainly when it comes to use a string to refer an array index. Consider the following case:

$colors = array(
'r'=>"red",
'b'=>"blue"
);
$vr = "colors[r]"; //I tried even this "color['r']"
echo $$vr; // I tried even this ${$vr}

Can anyone tell if it is possible to do the above. expected o/p is red using "color[r]" as string and then using it as variable.

Variable variables are more complicated and less powerful then plain arrays / associative arrays. Just don't use them. — Quentin, Jul 07 '13 at 08:59
http://stackoverflow.com/questions/4179489/double-dollar-sign-php — Emilio Gort, Jul 07 '13 at 09:02
Can there be any alternate solution for this other than just using the plain array/associative array — Nishant, Jul 07 '13 at 09:03
I believe you should change `$vr = $colors['r'];`, so that `$vr` contains `"red"`. `$$vr` would then evaluate to `$red`. — Sumurai8, Jul 07 '13 at 09:05

score 0 · Answer 1 · edited Jul 07 '13 at 09:31

0

You can't do that directly. Consider the following:

$varName = array_shift(explode('[', $vr));

foreach($$varName as $key=>$value){
    echo $key.": ".$value."<br />";
}

this will print out:

r: red
b: blue

The variable variable is just the first part (colors). You can't include the key in this.

edited Jul 07 '13 at 09:31

mnagel

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answered Jul 07 '13 at 09:25

Swissdude

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the array can be deeper, to next level i.e. it could have been, $colors['r']['shade']. What if its the following case: $vr = "colors['r']['shade']". Its dynamic and the depth of array can be anything. – Nishant Jul 08 '13 at 04:55
Then you'd have to write your own parser. But before I go deeper into that: What's the goal of this all? Why are you doing what you're doing? ;) – Swissdude Jul 08 '13 at 11:25

Variable variable with arrays

1 Answers1