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
曾经蜡笔没有小新2017-05-16 13:11:31
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);
我想大声告诉你2017-05-16 13:11:31
?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']
迷茫2017-05-16 13:11:31
Actually, what you wrote is correct, don’t rush to ask, take a look at your code
巴扎黑2017-05-16 13:11:31
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));
伊谢尔伦2017-05-16 13:11:31
$m = ['a'=>['b'=>['c'=>'@@@@@']]];
$x = 'a.b.c';
echo array_reduce(explode('.', $x), function($s, $i) { return $s[$i]; }, $m);
滿天的星座2017-05-16 13:11:31
If you use laravel framework,
$m = [ 'a'=>['b'=>['c'=>'@@@@@' ]]];
$x = 'a.b.c';
$z = array_get($m,$x);
return $z;