PHP array as variable name

问题:

How to send an indexes name for php array vairable.

the array is

$array = array('Somthing'=>array('More'=>array('id'=> 34))); 

and now I want to display this thing but with a variable name I don't know how to explain so I write what I want to have.

$index_name = '[Something][More][id]';  $array{$index_name}; 

Is it possible in any way ?

回答1:

Not in one go like that. Here's how you'd do it:

$array['Something']['More']['id'] 

If you particularly wanted access multidimensional arrays with a single string, then you could build a function to do that:

function array_multi(Array $arr, $path) {     $parts = explode(".", $path);      $curr =& $arr;     for ($i = 0, $l = count($parts); $i < $l; ++$i) {         if (!isset($curr[$parts[$i]])) {             // path doesn't exist             return null;         } else if (($i < $l - 1) && !is_array($curr[$parts[$i]]) {             // path doesn't exist             return null;         }         $curr =& $curr[$parts[$i]];     }     return $curr; }  // usage: echo array_multi($array, "Something.More.id");    // 34 echo array_multi($array, "Something.More");       // array("id" => 34) 

回答2:

Recursive version supporting your syntax with square brackets:

$array = array('Something'=>array('More'=>array('id'=> 34)));  $string = '[Something][More][id]';  echo scan_array($string, $array);  function scan_array($string, $array) {     list($key, $rest) = preg_split('/[[\]]/', $string, 2, PREG_SPLIT_NO_EMPTY);     if ( $key && $rest ) {         return scan_array($rest, $array[$key]);     } elseif ( $key ) {         return $array[$key];     } else {         return FALSE;     } } 

回答3:

Ok, I know this is how people get shot. But c'mon, eval() is not always the wrong answer.

$array = array('Something'=>array('More'=>array('id'=> 34))); $index_name = '[Something][More][id]'; eval('$val = $array'.$index_name.';'); // Wrap in a function or something 

回答4:

You could do this with eval():

<?php  $array = array('Somthing'=>array('More'=>array('id'=> 34))); $index_name = "['Somthing']['More']['id']";  $stmt='echo $array'.$index_name.';'; eval($stmt);  ?> 

---

UPDATE:

It seems some SO users are uncomfortable with the idea of using eval(). I think it makes sense to read this thread which discusses the pros and cons before deciding whether to use this in your own code.

回答5:

If you've cornered yourself into needing to do something like this, there's a pretty good chance you've done something else in a poor way. There's valid reasons to do this, but not very often.

function key_path($arr, $keys) {     return $keys ? key_path($arr[array_shift($keys)], $keys) : $arr; }  $arr['Something']['More']['id'] = 34; $keys = array('Something', 'More', 'id');  var_dump( key_path($arr, $keys)); 

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