CODEWITHSUNDEEP
javascriptjqueryhtml
Nick Tirrell
Nick Tirrell

Reputation: 431

JavaScript: Count instances of specific integers in a string

OKAY, so I have a bunch of numbers in a div, lets say something like...

<div id="countme">7, 5, 6, 0, 3, 0, 5, 3, 3, 2, 8</div>

And I want to use JavaScript to return...

Example Output: "(2,0),(1,2),(3,3),(2,5),(1,6),(1,7),(1,8)"

Explained: Zero appears two times, two appears one time, three appears three times, etc...

I've tried the following...

var str = document.getElementById('countme').innerText;
var match = str.match(/7/g);
var match1 = str.match(/5/g);
alert(match.length);
alert(match1.length);

But I need it to display the number it searched for, and I need everything to be in one alert.

Any thoughts?

Thanks! :)

Upvotes: 2

Views: 370

Answers (4)

Blue
Blue

Reputation: 463

I think this is almost as efficient as you can get. It also serves as a general count unique matches method:

var testString = document.getElementById('countme').innerText;
count = {}; 
var regX = /(\d+)/g;
var res;
while (res = regX.exec(testString )) {
    count[res[0]] = (count[res[0]] !== undefined ? ++count[res[0]] : 1)
};

Upvotes: 0

Reinstate Monica Cellio
Reinstate Monica Cellio

Reputation: 26163

Try this...

var str = "7, 5, 6, 0, 3, 0, 5, 3, 3, 2, 8";
str = str.replace(/\s/g, "");
str = str.split(",");

var result = {};

str.forEach(function(value) {
    if (result[value]) {
        result[value]++;
    }
    else {
        result[value] = 1;
    }
});

var output = "";

for(value in result) {
    output += (output == "" ? "" : ",") + "(" + value + "," + result[value] +")";
}

alert(output);

It splits the string and removes any whitespace, so you're left with an array (and no assumption that the delimiter is consistent).

It then creates an object representing each value and the count.

It finally converts that into an output, similar to the one in your example.

Upvotes: 0

Vishnu Ravi
Vishnu Ravi

Reputation: 46

Here is the Answer

var str    = document.getElementById('countme').innerText;
var array  = JSON.parse("[" + str+ "]");
var counts = {};
array.forEach(function(x) { counts[x] = (counts[x] || 0) + 1; });
console.log(counts);

Upvotes: 0

omarjmh
omarjmh

Reputation: 13896

JSBIN: https://jsbin.com/tesezoz/1/edit?js,console 

var str = "7, 5, 6, 0, 3, 0, 5, 3, 3, 2, 8";

// first get the numbers
var m = str.split(', ').map(Number);

// turn it into an object with counts for each number:

var c = m.reduce(function(a, b) {
  a[b] = ++a[b] || 1;
  return a;
}, {});

// now you have an object that you can check for the count
// which you can alert... its the c variable

Upvotes: 1

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