converting string to integer in Javascript

Question

I am reading some values from an xml file using JavaScript. Since it is a string, i need to convert it to integer and perform some calculations.

For reading the data from XML file I use this code:

var pop = JSON.stringify(feature.attributes.Total_Pop.value);

which works fine. later I use the following code to convert it to integer:

var popint = parseInt(pop);

This also works fine. But later when I use it to do some math, it returns NAN.

the code I use for Math operation is:

var pop6 = Math.ceil(popint / 30);

What am I doing wrong? any suggestions?

That depends on what the string is, but perhaps you could simply parseInt(popint, 10) / 30. Ref. parseInt(). — David Thomas
– David Thomas, Commented Nov 27, 2013 at 16:12
Try giving the parseInt function a base value, and you might want to make it a float, not everything /30 is a whole number. — Sterling Archer
– Sterling Archer, Commented Nov 27, 2013 at 16:12
Have you done any basic debugging? console.log( popint ); console.log( typeof popint );? — JJJ
– JJJ, Commented Nov 27, 2013 at 16:12
If you are getting NaN that means the string parsed was not actually an integer — chancea
– chancea, Commented Nov 27, 2013 at 16:14
+ there's not enough information here to give an answer; obviously if popint = parseInt( pop ) "works fine" (i.e. is an integer) then Math.ceil( popint / 30 ) can't be NaN unless the value of popint has changed somewhere in between. — JJJ
– JJJ, Commented Nov 27, 2013 at 16:15

McGarnagle · Accepted Answer · 2013-11-27 16:14:02Z

3

Don't stringify -- just use var pop = feature.attributes.Total_Pop.value;. Calling JSON.stringify wraps the string in extra quotation marks.

var pop = "123";                    // "123"
var popint = parseInt(pop);         // 123

Vs:

var pop = JSON.stringify("123");    // ""123""
var popint = parseInt(pop);         // NaN

answered Nov 27, 2013 at 16:14

McGarnagle

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