Filter array from big data collection of data

Question

I have 2 arrays one is the collection of key and other with a collection of data ex.

$array1 = ['0'=>'A1','1'=>'A2','2'=>'A3']; 

and

$array2 = ['A1'=>'Data1','A2'=>'Data2','A3'=>'Data3','A4'=>'Data4','A5'=>'Data5']; 

I want data like this

$array = ['A1'=>'Data1','A2'=>'Data2','A3'=>'Data3']

Answer 1

you can use array_filter for this:

$my_array = ['A1'=>'Data1','A2'=>'Data2','A3'=>'Data3','A4'=>'Data4','A5'=>'Data5'];
$allowed  = ['0'=>'A1','1'=>'A2','2'=>'A3']; 
$filtered = array_filter(
    $my_array,
    function ($key) use ($allowed) {
        return in_array($key, $allowed);
    },
    ARRAY_FILTER_USE_KEY
);

var_dump($filtered);

Output:

array(3) {
  ["A1"]=>
  string(5) "Data1"
  ["A2"]=>
  string(5) "Data2"
  ["A3"]=>
  string(5) "Data3"
}

Demo: https://3v4l.org/ZvkJb

Credit: PHP: How to use array_filter() to filter array keys?

Answer 2

You can also try this one to get the exact data of $array2 as you mentioned in the question.

$array1 = ['0'=>'A1','1'=>'A2','2'=>'A3']; 
$array2 = ['A1'=>'Data1','A2'=>'Data2','A3'=>'Data3','A4'=>'Data4','A5'=>'Data5']; 
$ans = [];
foreach($array1 as $value)
{
    if(isset($array2[$value]))
        $ans[$value] = $array2[$value];
}
print_r($ans);

Answer 3

You can make $array1 a dic, then check if key in $array2 is set in the dic.

$array1 = array_flip($array1);
$result = [];
foreach($array2 as $k => $v){
    if(isset($array1[$k])){
        $result[$k] = $v;
    }
}