CODEWITHSUNDEEP
javascript
Andha
Andha

Reputation: 917

Javascript Sum Values

I need to sum several values in javascript. I've tried by using following code

var a = 2;
var b = 5;
c = a+b;

But, instead of calculating the values of a and b, the output (c) only combine those two values. So the output given is :

c = 25

I believe you guys can help me easily about this. Thx before. Regard Andha.

Upvotes: 11

Views: 115274

Answers (8)

Josias Maestre
Josias Maestre

Reputation: 127

-Is important to apply Number() to every value. The ideal way is:

var sum = 0
sum = Number('93') + Number('7')          //result 100

-instead of this way (careful with this)

var sum = 0
sum = Number('97' + '3')                  //result 937

-and careful with this (as variable is going to assign string type by default)

var sum = 0
sum = Number('97') + '3'                  //result "973"

Upvotes: 2

Artemiy Egorov
Artemiy Egorov

Reputation: 61

You can simply convert string to a number by adding + before it. For somebody can be more readable. Example:

const a = "2";
const b = "5";
const c = +a + +b

or const c = (+a) + (+b) may be more readable. That will first convert the string to a Number.

Upvotes: 0

Murugan Boopathi
Murugan Boopathi

Reputation: 21

Use parseInt():

var a=2;
var b=5;
c=parseInt(a)+parseInt(b);

Upvotes: 2

dMole
dMole

Reputation: 89

The author has probably put "simplified" code so we can get an idea. Had same problem, while getting input values. JS interpreted it as string. Using "Number()" solved the problem:

var sum = Number(document.getElementById("b4_f2_"+i).value) + Number(document.getElementById("b4_f3_"+i).value) + Number(document.getElementById("b4_f4_"+i).value);

Upvotes: 6

numbers1311407
numbers1311407

Reputation: 34072

Your code is adding (concatenating) strings. Are you sure that the code you posted represents your problem? What you have written should work. Be sure in the real code you're not saying:

var a = '2'; // or something similar

Or if the values are parsed from somewhere, be sure to call parseInt(a, 10) on them before doing the addition, 10 being the radix.

Or as pointed out in the comments the Number function would probably suit your purposes.

Upvotes: 8

kjetilh
kjetilh

Reputation: 4976

Make sure the values are numbers, otherwise they will concat instead of suming.

a = parseInt(a, 10); // a is now int

Upvotes: 13

JAAulde
JAAulde

Reputation: 19550

The code you show will not work the way you describe. It will result in 7.

However, when attempting to perform addition, if either or both numeric values are actually numeric strings, the other values will be cast to strings and they will be concatenated.

This is most likely to happen when attempting to read form values, reading cookies, or some other sort of HTTP header. To convert a string to a number, you need to use parseInt() [docs]. Read through the docs on it and be sure to pay attention to, and provide, the second parameter (radix) to ensure the casting from string to number uses the base you expect. (The lack of info on radix in other answers is the primary reason I went ahead and posted an answer even though others had already mentioned parseInt().)

Also, FYI, Another handy function to use when dealing with unknown values and hoping to perform mathematic operations is isNaN() [docs].

Upvotes: 2

Jordão
Jordão

Reputation: 56457

This works fine:

var a = 2; 
var b = 5; 
var c = a + b; // c is now 7

Upvotes: 2

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