Filter Json array

Question

This is my first time working with json and I'm having a hard time trying to filter an array I'm trying to get all values (tienda) where id_estado=1.

Any clue how to approach this?

JA1= [{"id_estado":"1","tienda":"Aurrera"},{"id_estado":"1","tienda":"Walt-Mart"},{"id_estado":"1","tienda":"Chedraui"},{"id_estado":"1","tienda":"Soriana"},{"id_estado":"1","tienda":"Comercial MX"},{"id_estado":"1","tienda":"City Market"},{"id_estado":"2","tienda":"Walt-Mart"},{"id_estado":"2","tienda":"Chedraui"},{"id_estado":"2","tienda":"Aurrera"},{"id_estado":"2","tienda":"Superama"}]

            JSONArray JA1=new JSONArray(result1);
        JSONObject json1= null;
        name = new String[JA1.length()];
            for (int i = 0; i < JA1.length(); i++) {
                 Log.d("LOG", "resultado name sin arreglo11 " + JA1);
                //name[i] = json1.getString("tienda");
                //name[i]=json1.getString("estado");
            }

        for(int i=0;i<name.length;i++)
        {
            list2.add(name[i]);
            Log.d("LOG", "resultado name2 " + name[i]);
        }

Thanks in advance

Hint: If you are filtering the array, the resultant array will likely be smaller. The size of the resultant array will not be known up-front, so you should use an ArrayList<String>, not a String[], to collection the result. — Andreas
– Andreas, Commented Sep 10, 2017 at 4:19

Ben P. · Accepted Answer · 2017-09-10 05:03:21Z

9

Here's how I'd do it:

    try {
        List<String> filtered = new ArrayList<>();
        JSONArray ary = new JSONArray(/* your json here */);

        for (int i = 0; i < ary.length(); ++i) {
            JSONObject obj = ary.getJSONObject(i);
            String id = obj.getString("id_estado");
            if (id.equals("1")) {
                filtered.add(obj.getString("tienda"));
            }
        }
    } catch (JSONException e) {
        // handle exception
    }

An explanation of this code:

Create an ArrayList to hold the filtered values.
Create a JSONArray from your json text.
Iterate over each element in the array, pulling out a JSONObject each time.
For each object, we get its id_estado property and check if it is equal to "1".
If it is, we add the tienda property to the list of filtered values.

edited Sep 10, 2017 at 5:03

answered Sep 10, 2017 at 4:20

Ben P.

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Sean Calkins · Accepted Answer · 2022-12-02 03:16:19Z

0

If you're using kotlin, you can create an extension method and pass in a validation function as a parameter

fun JSONArray.filter(validate: (JSONObject) -> Boolean): List<JSONObject> {
    val retVal = mutableListOf<JSONObject>()
    for (i in 0.until(length())) {
        try {
            val jsonObject = getJSONObject(i)
            if (validate(jsonObject)) {
                retVal.add(jsonObject)
            }
        } catch (e: Exception) {
            Log.d(TAG, "Exception: $e")
        }
    }
    return retVal
}

You can use it like this

val filteredArray = jsonArray.filter { it.getString("bar") == "foo" }

answered Dec 2, 2022 at 3:16

Sean Calkins

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phpdroid · Accepted Answer · 2017-09-10 04:43:04Z

0

try this

for (int i = 0; i < JA1.length(); i++) {
             JSONObject json_data = jsonArray.getJSONObject(i);
             name[i] = json_data.getString("tienda");

        }

we have to create object of each nested JSON item in the JSON using JSONObject json_data = jsonArray.getJSONObject(i); that was missing in your case.

answered Sep 10, 2017 at 4:43

phpdroid

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