PHP values from array where key is in another arra

问题:

I am struggling with this for some reason.

I have 2 arrays. The first is a standard array called colsArray that looks like this:

Array
(
    [0] => fName
    [1] => lName
    [2] => city
)

The second is a multidimensional array called query_data that looks like this:

Array
(
    [0] => Array
    (
        [recordID] => xxx
        [fName] => xxx
        [lName] => xxx
        [address1] => xxx
        [city] => xx
        [zip] => xxx
        [vin] => xxx
    )

[1] => Array
    (
        [recordID] => xxx
        [fName] => xxx
        [lName] => xxx
        [address1] => xxx
        [city] => xxx
        [zip] => xxx
        [vin] => xxx
    )

[2] => Array
    (
        [recordID] => xxx
        [fName] => xxx
        [lName] => xxx
        [address1] => xxx
        [city] => xxx
        [zip] => xxx
        [vin] => xxx
    )

[3] => Array
    (
        [recordID] => xxx
        [fName] => xxx
        [lName] => xxx
        [address1] => xxx
        [city] => xxx
        [zip] => xxx
        [vin] => xxx
    )

)

I just need to use those 2 arrays to create a new array that has all the data from the query_data array where the keys are in the fist array colsArray. The new array would look like this:

Array
(
    [0] => Array
    (

        [fName] => xxx
        [lName] => xxx
        [city] => xx

    )

[1] => Array
    (
        [fName] => xxx
        [lName] => xxx
        [city] => xx
    )

[2] => Array
    (
        [fName] => xxx
        [lName] => xxx
        [city] => xx
    )

[3] => Array
    (
        [fName] => xxx
        [lName] => xxx
        [city] => xx
    )
)

Any help on this would be great.

Thanks!

回答1:

PHP offers a variety of array functions, and you usually get away with just combining a bunch of those:

$keys = array_flip($colsArray);
$new_data = array();

foreach($query_data as $key => $data) {
    $new_data[$key] = array_intersect_key($data, $keys);
}

Alternatively, a more functional style, but more memory intensive:

$new_data = array_map(
    'array_intersect_key', // or just array_intersect_key in newer PHP versions 
    $query_data, 
    array_pad(array(), count($query_data), array_flip($colsArray))
);

回答2:

$finalarr = [];
foreach ($query_data as $data) {
    $arr = [];
    foreach ($colsArray as $key){
       $arr[$key] = $data[$key];
    }
    $finalarr[] = $arr;
}

The [] notation for creating arrays is new, so you might have to use array() instead.