summing numbers stored in an array in JavaScript

Question

I want to sum a list of numbers stored in a JavaScript object. The object is created and updated using this code:

var myscore = $('input[name="Points1"]').val();
scorelist = JSON.parse(localStorage.getItem(playerName + 'scorelist') || '[]');
        scorelist.push(myscore);
        localStorage.setItem(playerName + 'scorelist', JSON.stringify(scorelist));
        $('div.scorecolumn', column).html("Score: <br>" + scorelist.join('<br>') + "<br>");

Basically I take whatever is in the column at the time, parse it, add myscore, stringify it, join each element with a <br> and write the list to the scorecolumn. The list of numbers is saved as an object. My goal is to sum up all the numbers in the object at any given time.

This script is inside of a function that passes in a bunch of parameters which is why some variables look undefined here.

Any help would be greatly appreciated! Thanks

UPDATE:

var nicTotalScore = nicScoreList.reduce(function(score, total) {
        return total + score;   
    }, 0);
    console.log(nicTotalScore); //12120
    console.log(nicScoreList); //["12", "12"]

UPDATE: If the score field is left blank when submitted, an empty string " " instead of a score. this is registering as a 0 when the reduce method goes through the array. This doesnt affect the total, but say, for example, i wanted to then find the average score, it throws it off. any ideas there? thanks

pimvdb · Accepted Answer · 2012-03-02 21:16:06Z

3

If you push() to scorelist, I'd be tempted to say it's likely an Array.

You could use reduce().

var total = scorelist.reduce(function(total, score) {
    return total + +score;
}, 0);

edited Mar 2, 2012 at 21:16

pimvdb

155k80 gold badges313 silver badges358 bronze badges

answered Feb 28, 2012 at 4:09

alex

492k205 gold badges890 silver badges992 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Tristian Over a year ago

Quite elegant the reduce function.

Nic Meiring Over a year ago

I'm not sure I really understand the reduce function. would you mind explaining more?

alex Over a year ago

@NicMeiring MDN has good documentation.

Nic Meiring Over a year ago

thanks. get it now. answer still concatenating instead of summing though. see updates.

alex Over a year ago

@NicMeiring You must be storing scores as strings. I'll update my answer.

|

Collectives™ on Stack Overflow

summing numbers stored in an array in JavaScript

1 Answer 1

7 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

7 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related