array element referred in a variable

jlive

I want this following code...

$foo['item1'] = 'item1value';
$a = "foo['item1']";
echo $$a;

...giving this following result:

item1value

But, it is not working. The result is a null string.
Is this a php bug ?
How to get the same in other ways ?

petitduc

$a=$foo['item1]; echo $a;

Using dynamic variables with arrays requires the use of braces.
So perhaps your code would work with
echo $a{$a} instead of echo $$a;

jlive

petitduc, I fear what I want is really ambitiious, maybe not possible...

what you propose is normal not-variable variables: not enough

the ${$a} syntax is for variable variables (btw, also $$a is working)

but what I want is a 2-variable variable: with the first variable I mean the array, with the second I mean its item. Those both have to be evaluated to get the final variable name.

I could write the code:

$a=$foo1[$foo2];
echo ${$a}

this exactly gives the result I want

Btw, I'd like a synthetic form to specify the content of $a with 1 only variable....

Other ideas?

Weedpacket

Originally posted by jlive
petitduc, I fear what I want is really ambitiious, maybe not possible...

It certainly sounds like you're making it way more complicated than necessary. You do know that arrays can contain arrays? You can have $a[$foo1][$foo2]?

Failing that you can look at

$a='foo1';
${$a}[$foo2];

jlive

Yes, I redirected to simpler solution

Btw, the original problem was:
a function read a php array from a file. the function does not know the array' structure. In the file could be, i.e:

$foo['a1']='alfa';
$foo['a1']='beta';
$foo['a2']='pi';
$foo['a2']='ro';
$foo['a2']='sigma';
$foo['a3']='x';
$foo['a3'][0]='y';
$foo['a3'][1]='z';

In all the solution discussed, an array name and an item name is given in input to the function, through two separate variables: so, the function is required to know how to compose the input tokens in something matching the array in the file. Here is the problem.

If I set one only variable this way (i.e.):

$a = "foo['a2']";

then I can call the function this way:

foofunction ($a)

and I could have the function easily returning:

sigma

without the foofunction knowing the array structure in the file, if $a could be evaluated as a variable name....