Rounding with 2 decimals when convert from string to float

Question

When I round of the number 1.4034 to two decimals I get 1.4 instead of 1.40. How do I get 1.40? I can use toFixed(2) but that returns a string. I need it to be a float. Any ideas?

Here's my code

var num = 1.40345;
var stringnumber = Math.round(num * 100) / 100;

Update: The reason I want to this is because I'm using the chart library highchart which only excepts float values. The float value is printed on each bar and it looks odd when some values are with one decimal and some with two.

Check this:http://stackoverflow.com/questions/2221167/javascript-formatting-a-rounded-number-to-n-decimals/2909252#2909252 — AllTooSir, Apr 20 '13 at 14:10

score 0 · Answer 1 · answered Apr 20 '13 at 14:09

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This is silly. 1.40 === 1.4... Why could you possibly want 1.40 as a float?

Basically, it's impossible.

For example, try this.

parseFloat('1.40')

You'll just end up with 1.4 again.

answered Apr 20 '13 at 14:09

Nate Higgins

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score 0 · Answer 2 · edited Apr 17 '14 at 17:11

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When stringnumber is a number, it makes no difference for 1.4 and 1.40, because 1.4.toFixed(2) is "1.40".

The precision only matters when you print it out, i.e. as a string.

edited Apr 17 '14 at 17:11

Ivan Filković

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answered Apr 20 '13 at 14:13

yzn-pku

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score 0 · Answer 3 · answered Apr 20 '13 at 14:16

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1.4 vs 1.40 only has merits when you are talking about a visual representation like printing a string.

When talking about the datatype Number you cannot distinguish between 1.4 and 1.40 since that is exactly the same thing.

answered Apr 20 '13 at 14:16

Jacob T. Nielsen

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Rounding with 2 decimals when convert from string to float

3 Answers3