CODEWITHSUNDEEP
javascriptd3.js
user4556747
user4556747

Reputation:

How to get the total number of rows with particular value in json file in d3.js

I have a JSON file which I am using for visualization using d3.js. I want to get the count of total rows for a particular code. I am using the following for doing so:

data.keys(d.code).length

But its not working. How can I solve this? I have found one idea but it is not showing correct values. Whats the wrong with it?

Object.keys(d.code).length

I have a JSON file with following sample data

[
{"name":"a","code":20},
{"name":"b","code":20},
{"name":"c","code":20},
{"name":"d","code":21}

]

My target is to get the count of data with same code. For example for code 20 I should get 3 as output.

Upvotes: 0

Views: 1530

Answers (3)

altocumulus
altocumulus

Reputation: 21578

You might as well use d3.nest() to group your data based on code and have it return the number of entries per group:

var json = [
    {"name":"a","code":20},
    {"name":"b","code":20},
    {"name":"c","code":20},
    {"name":"d","code":21}
];

var nest = d3.nest()
  .key(function(d) { return d.code; })
  .rollup(function(values) { return values.length; })
  .entries(json);

Upvotes: 1

Jared Price
Jared Price

Reputation: 5375

var count = 0;
var length = data.length;

for (var x = 0; x < length; x++)
{
    if (data[x].code == 20)
        count++;
}

console.log('Final count: ' + count);

Probably something like that.

If you want a function you could use this:

var getCount = function(data, val)
{
    var count = 0;
    var length = data.length;

    for (var x = 0; x < length; x++)
    {
        if (data[x].code == val)
            count++;
    }

    return count;
}

Then call it like this:

var count = getCount(data, 20); // should return 3

Upvotes: 0

Stephen Thomas
Stephen Thomas

Reputation: 14053

You don't need D3.js for this. Simple JavaScript should do it. Something like:

total = data.reduce(function(count, entry) { 
    return count + (entry.code === 20 ? 1 : 0);
}, 0);

Obviously, you can convert it to a function to handle arbitrary values other than 20.

Upvotes: 0

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