how to get all elements of array that have ids that are in another array-CodePudding

suppose that I have an array. each element is another array which has "id", "name", "age" etc. keys.

$students = array(
    array(
        "id"=>1,
        "name"=>"Alice",
        "age"=>22
    ),
    array(
        "id"=>3,
        "name"=>"Bob",
        "age"=>22
    )
    ,array(
        "id"=>4,
        "name"=>"carol",
        "age"=>22
    )
);

now I have another array containing some IDs ,$ids = array(1,4); how do I get the elements in first array that have ids that are in the second array.

expected result:

Array
(
[0] => Array
    (
        [id] => 1
        [name] => Alice
        [age] => 22
    )

[2] => Array
    (
        [id] => 4
        [name] => carol
        [age] => 22
    )

)

what about the case in which the first array is an array of objects instead of array of arrays?

I tried array_intersect and array_intersect_key but they are not built for this purpose. should I use array_map?

CodePudding user response：

As per the suggestion made above by @CBroe, you can solve the filtering of the source array like this.

$students = array(
    array(
        "id"=>1,
        "name"=>"Alice",
        "age"=>22
    ),
    array(
        "id"=>3,
        "name"=>"Bob",
        "age"=>22
    )
    ,array(
        "id"=>4,
        "name"=>"carol",
        "age"=>22
    )
);

$ids=array(1,4);

/*
    Array filter with an anonymouse callback that 
    `uses` the IDs array ( could use a global )
    and performs a simple `in_array` test - returning
    that value if true.
*/
$result=array_filter( $students, function( $item ) use( $ids ){
    return in_array( $item['id'], $ids );
});


printf('<pre>%s</pre>',print_r($result,true));

which yields the desired output:

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => Alice
            [age] => 22
        )

    [2] => Array
        (
            [id] => 4
            [name] => carol
            [age] => 22
        )

)