PHP搜索JSON而不循环

Question

I have a large JSON array which is the result of querying the API of an Icinga2 monitoring system.

I have used json_decode like this in my code to decode it:

$response = json_decode($array, true);

and I can see the output looks like this:

        Array
            (
                [results] => Array
                    (
                        [0] => Array
                            (
                                [attrs] => Array
                                    (
                                        [__name] => HOSTNAME0
                                        [acknowledgement] => 0
                                        [acknowledgement_expiry] => 0
                                        ...
                                        ...
                                        [state] => 0
                                        [state_type] => 1
                                 [meta] => Array
                                     (
                                     )

                                 [name] => HOSTNAME0
                                 [type] => Host
            )


                        [1] => Array
                            (
                                [attrs] => Array
                                    (
                                        [__name] => HOSTNAME1
                                        [acknowledgement] => 0
                                        [acknowledgement_expiry] => 0
                                        ...
                                        ...
                                        [state] => 0
                                        [state_type] => 1   
                                 [meta] => Array
                                     (
                                     )

                                 [name] => HOSTNAME1
                                 [type] => Host
            )

There are 400 Records in total and it's quite a complex structure but the only bits I am really interested in are the name and state fields. Basically my script has a list of 150 hostnames from another source and what I want to do is for each hostname, search for it in the array and return the value of the state field for that host. So far I've been struggling to do this without looping through the entire array for each of the 150 hostnames. There must be a more efficient way to do a lookup in the array based on a hostname and return a single value but I can't figure it out.

Answer 1

Given, the name field has no logical sorting inside the json result, there is no way to look at least once at each element. If they are sorted alphabetical, you could use a simple binary search, which would give you the result in O(log(n)).

The other thing is, if you have to search for multiple names, you could put them inside an name assiciated array. This way, you only have an initial overhead of O(n) building the list and each following search would return you the state on O(1).

// building the array
$states = [];
foreach ($items as $item) {
    $states[$item['name']] = $item['state'];
}

looking for HOSTNAME1
$state = $states['HOSTNAME1'];