Build an array index from a string

[BravoFoxtrot]

Hi,

I'm trying to build an index into a multi dimensional associative
array. I may not know how many dimensions there are so i want to pass
the array indexes as a variable.

$arrayToAccess = array( array('Data'=>array('id'=>1,
'title'=>'Manager')),
array('Data'=>array('id'=>1,
'title'='Clerk')) );

$index = "['Data']['title']";
// or $index=''; if this is a single dim array ie $arrayToAccess =
array('Manager', 'Clerk');

foreach ( $arrayToAccess as $data {
$foundTitle = ${data.$index};
// do something to found title
}

Is there a way to do this in php without have to build a looping
structure?

[Michael Fesser]

..oO(BravoFoxtrot)

>I'm trying to build an index into a multi dimensional associative
array. I may not know how many dimensions there are so i want to pass
the array indexes as a variable.

$arrayToAccess = array( array('Data'=>array('id'=>1,
'title'=>'Manager')),
array('Data'=>array('id'=>1,
'title'='Clerk')) );

$index = "['Data']['title']";
// or $index=''; if this is a single dim array ie $arrayToAccess =
array('Manager', 'Clerk');

foreach ( $arrayToAccess as $data {
$foundTitle = ${data.$index};
// do something to found title
}

Is there a way to do this in php without have to build a looping
structure?

Yes, with eval(). But eval() is evil and inefficient. You better use a
more simple form for your index, which can easily be split into parts,
e.g.

$index = 'data/title';

Split it, either with explode() or step-by-step with strtok(), and then
loop through your array to find the element you want.

Micha

[BravoFoxtrot]

On May 27, 1:44 pm, Michael Fesser <[e-mail]:

.oO(BravoFoxtrot)

I'm trying to build an index into a multi dimensional associative
array. I may not know how many dimensions there are so i want to pass
the array indexes as a variable.

$arrayToAccess = array( array('Data'=>array('id'=>1,
'title'=>'Manager')),
array('Data'=>array('id'=>1,
'title'='Clerk')) );

$index = "['Data']['title']";
// or $index=''; if this is a single dim array ie $arrayToAccess =
array('Manager', 'Clerk');

foreach ( $arrayToAccess as $data {
$foundTitle = ${data.$index};
// do something to found title
}

Is there a way to do this in php without have to build a looping
structure?

Yes, with eval(). But eval() is evil and inefficient. You better use a
more simple form for your index, which can easily be split into parts,
e.g.

$index = 'data/title';

Split it, either with explode() or step-by-step with strtok(), and then
loop through your array to find the element you want.

Micha

Thanks for the tip. I came up with this function on the dentist's
chair this afternoon.

$arrayToAccess = array(
array('Data'=>array('id'=>1, 'title'=>'Manager')),
array('Data'=>array('id'=>1, 'title'=>'Clerk'))
);

echo getVal($arrayToAccess, array(0,'Data','title'));
echo "\n";
var_dump($arrayToAccess);

function getVal($array, $index)
{
foreach ( $index as $i )
{
$array = $array[$i];
}
return $array;
}
The result of getVal is "Manager"

[C. (http://symcbean.blogspot.com/)]

On May 27, 10:51 pm, BravoFoxtrot <[e-mail]:

On May 27, 1:44 pm, Michael Fesser <[e-mail]:

.oO(BravoFoxtrot)

>I'm trying to build an index into a multi dimensional associative
>array. I may not know how many dimensions there are so i want to pass
>the array indexes as a variable.

>$arrayToAccess = array( array('Data'=>array('id'=>1,
>'title'=>'Manager')),
array('Data'=>array('id'=>1,
>'title'='Clerk')) );

>$index = "['Data']['title']";
>// or $index=''; if this is a single dim array ie $arrayToAccess =
>array('Manager', 'Clerk');

>foreach ( $arrayToAccess as $data {
$foundTitle = ${data.$index};
// do something to found title
>}

>Is there a way to do this in php without have to build a looping
>structure?

Yes, with eval(). But eval() is evil and inefficient. You better use a
more simple form for your index, which can easily be split into parts,
e.g.

$index = 'data/title';

Split it, either with explode() or step-by-step with strtok(), and then
loop through your array to find the element you want.

Micha

Thanks for the tip. I came up with this function on the dentist's
chair this afternoon.

$arrayToAccess = array(
array('Data'=>array('id'=>1, 'title'=>'Manager')),
array('Data'=>array('id'=>1, 'title'=>'Clerk'))
);

echo getVal($arrayToAccess, array(0,'Data','title'));
echo "\n";
var_dump($arrayToAccess);

function getVal($array, $index)
{
foreach ( $index as $i )
{
$array = $array[$i];
}
return $array;

}

The result of getVal is "Manager"

It looks as if you're trying (badly) to implement second and third
normal forms using arrays - I can't see from your code what you're
trying to achieve but the route you are taking is a dead end.

Depending on what it is you really want to do with your data, maybe
you just need:

$data=array();
$data[]=array('1'=>'Manager');
$data[]=array('1'=>'Clerk');

or perhaps:
$data[]=array('id'=>1, 'title'=>'Manager');
$data[]=array('id'=>1, 'title'=>'Clerk');

Regardless it's a very inefficient **collection** unless you use
indexing on the outer keys of the array...something like
$data=array();
$data['Manager']=array(1=>'first',2=>'second'...);
$data['Clerk']=array(1=>'first'....);

C.

[Michael Fesser]

..oO(C. (http://symcbean.blogspot.com/))

>It looks as if you're trying (badly) to implement second and third
normal forms using arrays - I can't see from your code what you're
trying to achieve but the route you are taking is a dead end.

He has a tree-like structure of nested arrays and wants to have a
convenient way to access any arbitrary element fromt the tree by just
specifying the path to it. Nothing special. And the function he found at
the dentist seems to work fine.

In my own applications I use something similar (slightly more complex)
to store various values in a kind of registry, which is simply an array
tree. I can specify the requested key as 'application/database/tables'
for example and get the value stored there with something like

$tables = $registry->getValue('application/database/tables');

The getValue() method then simply splits the passed string and walks
down the registry array tree to find the value I want, quite similar
to the situation we have here. It becomes even more convenient with
implementing the ArrayAccess interface in my registry class:

$tables = $registry['application/database/tables'];

Micha