一个有趣的数组取值简化函数，都来看看吧

Question

$arr=['a1'=>['b1'=>['c1'=>['d1','d2','d3'],'c2'=>['d1','d2','d3'],],'b2'=>['c1'=>['d1','d2','d3'],'c2'=>['d1','d2','d3'],]],'a2'=>['b1'=>['c1'=>['d1','d2','d3'],'c2'=>['d1','d2','d3'],],'b2'=>['c1'=>['d1','d2','d3'],'c2'=>['d1','d2','d3'],]],];有上面一个数组，现在想通过三个参数（$a,$b,$c），来动态的取数组中值。情况如下：1、如果三个参数全为空，返回$arr；2、如果$a不为空，返回$arr[$a]；3、如果$a、$b不为空，返回$arr[$a][$b]；4、如果$a、$b、$c不为空，返回$arr[$a][$b][$c]；函数的形参可以是三个参数，或者是数组，或者动态获取传入的参数。我写了两个函数，总感觉不太简单，特来请教。//函数1functionthe_array($a='',$b='',$c=''){$arr=['上面那个数组'];$brr=array_filter([$a,$b,$c]);switch(count($brr)){case1:return$arr[$a]??[];break;case2:return$arr[$a][$b]??[];break;case3:return$arr[$a][$b][$c]??[];break;default:return$arr;break;}}//函数2functionthe_array(...$param){$arr=['上面那个数组'];$brr=array_filter($param);//或者用func_get_args()获取传入的参数switch(count($brr)){case1:$a=$param;return$arr[$a]??[];break;case2:[$a,$b]=$param;return$arr[$a][$b]??[];break;case3:[$a,$b,$c]=$param;return$arr[$a][$b][$c]??[];break;default:return$arr;break;}}

Answer 1

$arr=[
'a1'=>[
'b1'=>[
'c1'=>['d1','d2','d3'],
'c2'=>['d1','d2','d3'],
],
'b2'=>[
'c1'=>['d1','d2','d3'],
'c2'=>['d1','d2','d3'],
]
],
'a2'=>[
'b1'=>[
'c1'=>['d1','d2','d3'],
'c2'=>['d1','d2','d3'],
],
'b2'=>[
'c1'=>['d1','d2','d3'],
'c2'=>['d1','d2','d3'],
]
],
];
functionarray_get($arr,...$flag){
if(empty($flag)){
return$arr;
}
foreach($flagas$item){
if(!isset($arr[$item])){
//TODOReturn$arrornull
returnnull;
}
$arr=$arr[$item];
}
return$arr;
}
$result=array_get($arr,'a1','b1','c1');
var_dump($result);
建议学习Laravel的Arr::get()
framework/Arr.phpat5.4·laravel/framework