php select array by path

Question

May I get help to know whether this is possible?

I want to select array dynamically.

For instance,

$oj = (object)['A' => (object)['B' => (object)['C' => (object)['D' => []]]]]

$E = 'A'
$oj->$E // this will work

$E = 'A->B'  
$oj->$E // this will not work

What else I can do except to write a full path? Or maybe please tell me whether this is possible or is there any example I can refer?

$oj[A][B][C][D]     <---NO
$oj->A->B->C->D     <---NO

$E = A->B->C->D    
$oj->E              <--What I want   


Question Update: 

$oj->E = 'Store something'  <-What I want, then will store into $oj.

//So E here is not pick up the value of D, but the path of D;

Thank you very much.

Looking for this $oj[A[B[C[D]]]] ?

Nir Alfasi
– Nir Alfasi

2013-11-14 23:29:06 +00:00
Commented Nov 14, 2013 at 23:29 — Nir Alfasi
– Nir Alfasi, Commented Nov 14, 2013 at 23:29

Jan Turoň · Accepted Answer · 2013-11-15 00:27:25Z

3

You can explode the path by -> and trace the object part by part of the path:

function getPath($obj,$path) {
  foreach(explode('->',$path) as $part) $obj = $obj->$part;
  return $obj;
}

Example

$oj = (object)['A' => (object)['B' => (object)['C' => (object)['D' => []]]]];
$E = 'A->B->C->D';
getPath($oj,$E);

If you also want to write, you can do it ugly, but simple way using eval:

eval("\$tgt=&\$oj->$E;"); // $tgt is the adress of $oj->A->B->C->D->E
print_r($tgt); // original value of $oj->A->B->C->D->E
$tgt = "foo"; 
print_r($oj); // $oj->A->B->C->D->E = "foo"

edited Nov 15, 2013 at 0:27

answered Nov 14, 2013 at 23:48

Jan Turoň

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1 Comment

Micah Over a year ago

thank you very much, question updated, your example will only pick up the value of D, and what I want is selecting the path

aib · Accepted Answer · 2013-11-15 00:28:01Z

2

Short answer: No.

Long answer:

Are you possibly looking for references? OK, probably not.

In any case you're probably better off writing your own set of classes or functions, e.g.:

setUsingPath($oj, 'A->B->C->D', $x);
$x = getUsingPath($oj, $E);

But if you're sure what you want is the best solution to the (unspecified) problem and $E = 'A->B'; $oj->E... is the syntax to go with, it should be possible with shudder magic methods. A set of recursive shudder __get()s should do the trick.

answered Nov 15, 2013 at 0:28

aib

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