PHP Dynamic array key [duplicate] - php

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Closed 11 years ago.
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Dynamic array keys
I have an array $Values
which is set up like this
$Values
1
2
3
a
b
c
4
which is nested.
and I have a key like this: $key = "a"]["b"]["c";
Can I now do: Values[$key], ti get the value in c ?
#Edit
Simply said: I want to get the value from array $Values["a"]["b"]["c"] By doing $Values[$key]. What should my key be then?

Answer 1

No, but you can extract the result:
$Values = array( '1' => 'ONE',
'2' => 'TWO',
'3' => 'THREE',
'a' => array( 'b' => array( 'c' => 'alphabet') ),
'4' => 'FOUR'
);
$key = '"a"]["b"]["c"';
$nestedKey = explode('][',$key);
$searchArray = $Values;
foreach($nestedKey as $nestedKeyValue) {
$searchArray = $searchArray[trim($nestedKeyValue,'"')];
}
var_dump($searchArray);
Will only work if $key is valid.
Now how do you get in a situation with a key like this anyway? Perhaps if you explained the real problem, we could give you a real answer rather than a hack.

Answer 2

No, you only can get individual keys from variables. Depending on what you really want to do you could use references to your array elements.

Answer 3

Nah you can't. This is invalid syntax.
Hover you can do:
$key = 'a,b,c';
// or:
$key = serialize( array( 'a','b', 'c'));
// or many other things
And than implement your array-like class which will implement ArrayAccess or ArrayObject (let's way you'll stick with $key = 'a,b,c';):
class MyArray extends ArrayAccess {
protected $data = array();
protected &_qetViaKey( $key, &$exists, $createOnNonExisting = false){
// Parse keys
$keys = array();
if( strpos( $key, ',') === false){
$keys[] = $key;
} else {
$keys = explode( ',', $key);
}
// Prepare variables
static $null = null;
$null = null;
$exists = true;
// Browse them
$progress = &$this->data;
foreach( $keys as $key){
if( is_array( $progress)){
if( isset( $progress[ $key])){
$progress = $progress[ $key];
} else {
if( $createOnNonExisting){
$progress[ $key] = array();
$progress = $progress[ $key];
} else {
$exists = false;
break;
}
}
} else {
throw new Exception( '$item[a,b] was already set to scalar');
}
}
if( $exists){
return $progress;
}
return $null;
}
public offsetExists( $key){
$exists = false;
$this->_getViaKey( $key, $exists, false);
return $exists;
}
// See that we aren't using reference anymore in return
public offsetGet( $key){
$exists = false;
$value = $this->_getViaKey( $key, $exists, false);
if( !$exists){
trigger_error( ... NOTICE ...);
}
return $value;
}
public offsetSet ( $key, $val){
$exists = false;
$value = $this->_getViaKey( $key, $exists, true);
$value = $val;
}
}
// And use it as:
$array = MyArray();
$array['a']['b']['c'] = 3;
$array['a,b,c'] = 3;
Or implement function:
public function &getArrayAtKey( $array, $key){
// Similar to _qetViaKey
// Implement your own non existing key handling
}