在php中获取json元素的数量

My json is this :

{
"id1527":{"stats":"true"},
"id6376373":{"stats":"true"},
"id63737":{"stats":"true"}
}

how can get count of all ids(like 'id1527' or 'id6376373'...)

Decode to an array and count the elements.

count(json_decode($json, true));

I hope you mean this.

$str = '{"id1527":{"stats":"true"},"id6376373":{"stats":"true"},"id63737":"stats":"true"},"x444":{"stats":"false"}}';

echo count(preg_grep("/^id(\d)+$/",array_keys(json_decode($str,true))));

This code snippet checks to see whether the top-level key of the JSON array has a preceding text "id" and take only those records into account.

After parsing the JSON, array_filter() to filter this just to the ones with a key that begins with id, and count() to count them:

count(array_filter(json_decode($json, true), function($key) {
    return substr($key, 0, 2) == "id";
}, ARRAY_FILTER_USE_KEY));