Dynamic path problem of an element of an array in php

Question

If I know the path of an element in the array, how do I get the value of this element?
The following code reports an error, how to solve it? Does anyone have any good ideas?

$m = ['a'=>['b'=>['c'=>'@@@@@']]];

$x = 'a.b.c';
$y = str_replace('.','\'][\'',$x);
$y = 'm[\''.$y.'\']';

echo $$y; 

An error will be reported:

Notice: Undefined variable: m['a']['b']['c'] in /web/root/index.php on line 9

Answer 1

Dynamic variable names are only valid for variables, not array elements. 'm["a"]["b"]["c"]'Even if $ is added in front, the entire string will be regarded as a variable, and naturally it cannot be found.

You can simply use a loop

$m  = ['a'=>['b'=>['c'=>'@@@@@']]];

$x = 'a.b.c';
$y = explode('.',$x);
$z = $m;
foreach ($y as $key => $value) {
    $z = $z[$value];
}

var_dump($z); 

Answer 2

?First of all, the variable $y after the echo you printed has one more $符号，其次如果你想获取@@@@@,直接$m['a']['b']['c']

Answer 3

Actually, what you wrote is correct, don’t rush to ask, take a look at your code

Answer 4

Personally, I think that when facing this kind of problem, we should consider using recursion to deal with it instead of using string replacement.

<?php

$data = [
    'a'=>[
        'b'=>[
            'c'=>'@@@@@'
            ]
        ]
    ];

$path = 'a.b.c';

$arr = explode('.',$path);

function test($arr, $data){
    if(array_key_exists($arr[0],$data)){
        if(count($arr) > 1){
            $key = array_shift($arr);
            return test($arr, $data[$key]);
        }else{
            return $data[$arr[0]];
        }
    }else{
        return null;
    }
}

var_dump(test($arr,$data));

Answer 5

$m  = ['a'=>['b'=>['c'=>'@@@@@']]];
$x = 'a.b.c';

echo array_reduce(explode('.', $x), function($s, $i) { return $s[$i]; }, $m);

Answer 6

If you use laravel framework,

$m = [ 'a'=>['b'=>['c'=>'@@@@@' ]]];
$x = 'a.b.c';
$z = array_get($m,$x);
return $z;