php - how to match a key value pair in a JSON -

[ {"category":["30","32","33"],"type":"30 days","price":"100","id":"0"}, {"category":["34","37","47"],"type":"30 days","price":"200","id":1}, {"category":["46"],"type":"40 days","price":"100","id":2} ] 

in above json, how category has type: 30days.

expected output as.

$categories = array{0=>30,1=>32,2=>33,3=>34,4=>37,4=>47}   

you can use array_walk as

$json = '[ {"category":["30","32","33"],"type":"30 days","price":"100","id":"0"}, {"category":["34","37","47"],"type":"30 days","price":"200","id":1}, {"category":["46"],"type":"40 days","price":"100","id":2} ]'; $arr = json_decode($json,true); $categories = array(); array_walk($arr,function($v,$k)use(&$categories,$arr){    if($v['type'] == "30 days"){        $categories = array_merge($categories,$v['category']);    } });