Remove all elements except one from JSONArray of JSONObjects

Question

I have a JSONArray (org.json) like this:

[
    { \"a\": \"a\" },
    { \"b\": \"a\" },
    { \"c\": \"a\" },
    { \"d\": \"a\" },
    { \"e\": \"a\" },
    { \"         


        

Answer 1

If you want to avoid using type casts, try:

private static final String JSON = "{\"arr\": [" +
        "{\"z\": \"z\"}," +
        "{\"a\": \"a\"}," +
        "{\"b\": \"b\"}," +
        "{\"c\": \"c\"}" +
        "]}";
. . .
JSONObject jsonObject = new JSONObject(JSON);
JSONArray array = jsonObject.getJSONArray("arr");
JSONArray filtered = new JSONArray();

for (int i = 0; i < array.length(); i++) {
    JSONObject sub = array.getJSONObject(i);
    if (sub.has("a")) {
         filtered.put(sub);
     }
}

jsonObject.put("arr", filtered);
System.out.println(jsonObject.toString());

Result:

{"arr":[{"a":"a"}]}