Count number of objects in json array

Question

I have a json array stored in a url like

http://localhost/heart/api/restApiController/dataset.json

Json array looks like this

[
    {
        Weight: "3",
        Smoking: "1",
        Exercising: "0",
        Food_habits: "0",
        Parents_HA: "1",
        Alcohol: "2",
        Occupation: "1",
        Working_hours: "4",
        Heart_Attack: "0"
    }, {
        Weight: "4",
        Smoking: "0",
        Exercising: "1",
        Food_habits: "0",
        Parents_HA: "1",
        Alcohol: "1",
        Occupation: "1",
        Working_hours: "2",
        Heart_Attack: "0"
    }, {
        Weight: "2",
        Smoking: "1",
        Exercising: "1",
        Food_habits: "0",
        Parents_HA: "1",
        Alcohol: "2",
        Occupation: "1",
        Working_hours: "4",
        Heart_Attack: "0"
    }
]

I want to count the number of objects in this array and how many objects are there which has Heart_attack:'0' value. How can I do this?

Answer 1

Make a ajax request to the url you mentioned and find the length of the array in the success callback of the request.

function callback (data) {
if (data) {
    var heartAttackCount = 0;
    console.log("Data Length: " + data.length);
    data.forEach(function (object) {
        if (object.hasOwnProperty('Heart_Attack') && object['Heart_Attack'] === "0") {
            ++heartAttackCount;
        }
    });
    console.log("Heart Attack Count: " + heartAttackCount);
}

Answer 2

Use .filter to get the array elements with Heart_attack = 0 and then apply .length

var arr; // Represent your array
arr.filter(function (item) { 
  return item.Heart_attack == 0; 
}).length;

Working example:

 var arr = [ { Weight: "3", Smoking: "1", Exercising: "0", Food_habits: "0", Parents_HA: "1", Alcohol: "2", Occupation: "1", Working_hours: "4", Heart_Attack: "0" }, { Weight: "4", Smoking: "0", Exercising: "1", Food_habits: "0", Parents_HA: "1", Alcohol: "1", Occupation: "1", Working_hours: "2", Heart_Attack: "0" }, { Weight: "2", Smoking: "1", Exercising: "1", Food_habits: "0", Parents_HA: "1", Alcohol: "2", Occupation: "1", Working_hours: "4", Heart_Attack: "0" } ]; var len = arr.filter(function (item) { return item.Heart_Attack == 0; }).length; document.write(len);