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I have a string : "-10.456" I want to convert it to -10.465 in decimal (using JavaScript) so that I can compare for greater than or lesser than with another decimal number.

Regards.

Louys Patrice Bessette
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Jayaraj PS
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    possible duplicate of [How do I Convert a String into an Integer in JavaScript?](http://stackoverflow.com/questions/1133770/how-do-i-convert-a-string-into-an-integer-in-javascript) – Mike Ante Oct 24 '14 at 16:07
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    Related: [How to convert string into float in javascript?](http://stackoverflow.com/q/642650/218196) – Felix Kling Oct 24 '14 at 16:10

5 Answers5

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The parseInt function can be used to parse strings to integers and uses this format: parseInt(string, radix);

Ex: parseInt("-10.465", 10); returns -10

To parse floating point numbers, you use parseFloat, formatted like parseFloat(string)

Ex: parseFloat("-10.465"); returns -10.465

Community
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Grice
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  • @Grice what if I am trying to add two decimal the trailing zeros are missing! +(parseFloat(3.6 + 4.4).toFixed(1)) if I use .toFixed it returns string and parseFloat return number but without decimal point/trailing zero – Santosh Jan 07 '19 at 19:06
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Simply pass it to the Number function:

var num = Number(str);
Felix Kling
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  • Number function only works if the number does not have any other, not a number string. if you have a '-10%' Number resolve NA – xzegga May 31 '22 at 16:36
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Here are two simple ways to do this if the variable str = "-10.123":

#1

str = str*1;

#2

str = Number(str);

Both ways now contain a JavaScript number primitive now. Hope this helps!

Drazzah
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1

In javascript, you can compare mixed types. So, this works:

var x = "-10.456";
var y = 5.5;
alert(x < y) // true
alert(x > y) // false
jmrah
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1

the shortcut is this: 

"-3.30" <--- the number in string form
+"-3.30" <----Add plus sign
-3.3 <----- Number in number type.
Muhammad Umer
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    It keeps the decimal fraction and the sign, and it appears to be the fastest in Chrome: http://jsperf.com/number-vs-plus-vs-toint-vs-tofloat/14 (note: some of the tests convert to int!). You can also use a minus instead of a plus to negate the number. It even supports e-notation! (`+"12.34e5"`) I don't understand why no one upvoted this. Are there portability issues? – CodeManX Sep 01 '15 at 22:08