php在assoc数组中找到公共密钥

Question

I have an array

  "a" => array:99 [▶]
  "b" => array:98 [▶]
  "c" => array:98 [▶]
  "d" => array:98 [▶]
  "e" => array:98 [▶]
  "f" => array:98 [▶]
  "g" => array:97 [▶]
  "h" => array:72 [▶]

.....

I need to filter the arrays by common keys. array a has 99 items and h has 72 items so I need to make all the arrays in this array the same 72 items based on the key.

array a:

"Johnson" => "2.94"
"Jordan" => "1.99"
"Bob" => "3.29"
"Bill" => "2.60"
"Jon" => "3.82"

......

array b:

"Johnson" => "2.94"
"Jordan" => "1.99"
"Bob" => "3.29"
"Bill" => "2.60"
"Steve" => "3.82"

......

so I essentially want the arrays a and b to be:

"Johnson" => "2.94"
"Jordan" => "1.99"
"Bob" => "3.29"
"Bill" => "2.60"

because these are the keys that are consistent across those 2 arrays.

I would need each of the arrays to have the same items based on the key that exists in all of the arrays.

Is there a way to do this if the arrays are part of the same array?

Answer 1

First apply array_intersect_key once with all the subarrays passed to it. This you can do with call_user_func_array: this will give you the result for the first item in your data. It will only have the keys remaining that also occur in all other items.

Then map the data with array_map by applying again array_intersect_key to intersect each item with that first item's result.

Assuming your input is stored in a variable named $data:

$first = call_user_func_array('array_intersect_key', $data);
$result = array_map(function ($item) use ($first) {
    return array_intersect_key($item, $first);
}, $data);

$result will have a copy of the data where each item will have the same keys (but still with their proper values of course).