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?

What have you tried so far? Please post an example of the relevant parts of your application. — Sly_cardinal
– Sly_cardinal, Commented May 22, 2016 at 6:02

Aditya Singh · Accepted Answer · 2016-05-22 06:05:58Z

1

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);

answered May 22, 2016 at 6:05

Aditya Singh

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3 Comments

CraZyDroiD Over a year ago

my array is not hard coded in my controller.. instead it's in the url I have given in the question. when it's in a url, how I can do this?

Aditya Singh Over a year ago

It's just an example assuming that you have the data. If you don't please provide the complete code you have

CraZyDroiD Over a year ago

I have the data but it's in a database table. so how to count when it's in a DB table?

kvn · Accepted Answer · 2016-05-22 06:05:35Z

0

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);
}

answered May 22, 2016 at 6:05

kvn

2,3005 gold badges25 silver badges49 bronze badges

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