var num = 20.3698 //20.37
var num = 0.36587 //0.37
var num = 0.000014247 //0.000014
var num = 0.0000000000099879 //0.000000000001
I am facing a problem in my JavaScript code: I have some random large and small decimal numbers which on printing takes too much space on view pane.
Example:
var num = 0.023810002044 is okay because here I can use toFixed(2) but numbers like this 0.00000000008824721 take much space and if I use toFixed(2) then it will give me 0.00 but I want 0.00000000009 and if given a number like 0.03248 then output should be 0.03.
You could take the logarithm of 10 and adjust smaller numbers.
const
fix = v => v > 0.01
? v.toFixed(2)
: v.toFixed(1 - Math.floor(Math.log10(Math.abs(v))));
console.log([20.3698, 0.36587, 0.000014247, 0.00000000008824721, 0.0000000000099879].map(fix));
I recently came up with this code while answering another StackOverflow question. Basically, on blur, this code will properly comma separate by thousands and leave the decimal at two digits (like how USD is written [7,745.56]).
I was wondering if there is more concise way of using regex to , separate and cut off excessive decimal places. I recently updated this post with my most recent attempt. Is there a better way of doing this with regex?
Input -> Target Output
7456 -> 7,456
45345 -> 45,345
25.23523534 -> 25.23
3333.239 -> 3,333.23
234.99 -> 234.99
2300.99 -> 2,300.99
23123123123.22 -> 23,123,123,123.22
Current Regex
var result;
var str = []
reg = new RegExp(/(\d*(\d{2}\.)|\d{1,3})/, "gi");
reversed = "9515321312.2323432".split("").reverse().join("")
while (result = reg.exec(reversed)) {
str.push(result[2] ? result[2] : result[0])
}
console.log(str.join(",").split("").reverse().join("").replace(",.","."))
As an alternative to the Regex, you could use the following approach
Number(num.toFixed(2)).toLocaleString('en-US')
or
num.toLocaleString('en-US', {maximumFractionDigits: 2})
You would still have the toFixed(2), but it's quite clean. toFixed(2) though won't floor the number like you want. Same with {maximumFractionDigits: 2} as the second parameter to toLocaleString as well.
var nums = [7456, 45345, 25.23523534, 3333.239, 234.99, 2300.99, 23123123123.22]
for (var num of nums)
console.log(num, '->', Number(num.toFixed(2)).toLocaleString('en-US') )
Flooring the number like you showed is a bit tricky. Doing something like (num * 100 | 0) / 100 does not work. The calculation loses precision (e.g. .99 will become .98 in certain situations). (also |0 wouldn't work with larger numbers but even Math.floor() has the precision problem).
The solution would be to treat the numbers like strings.
function format(num) {
var num = num.toLocaleString('en-US')
var end = num.indexOf('.') < 0 ? num.length : num.indexOf('.') + 3
return num.substring(0, end)
}
var nums = [7456, 45345, 25.23523534, 3333.239, 234.99, 2300.99, 23123123123.22]
for (var num of nums) console.log(num, '->', format(num))
function format(num) {
var num = num.toLocaleString('en-US')
var end = num.indexOf('.') < 0 ? num.length : num.indexOf('.') + 3
return num.substring(0, end)
}
(when changing to another format than 'en-US' pay attention to the . in numbers as some languages use a , as fractal separator)
For Compatibility, according to CanIUse toLocaleString('en-US') is
supported in effectively all browsers (since IE6+, Firefox 2+, Chrome
1+ etc)
If you really insist on doing this purely in regex (and truncate instead of round the fractional digits), the only solution I can think of is to use a replacement function as the second argument to .replace():
('' + num).replace(
/(\d)(?=(?:\d{3})+(?:\.|$))|(\.\d\d?)\d*$/g,
function(m, s1, s2){
return s2 || (s1 + ',');
}
);
This makes all your test cases pass:
function format(num){
return ('' + num).replace(
/(\d)(?=(?:\d{3})+(?:\.|$))|(\.\d\d?)\d*$/g,
function(m, s1, s2){
return s2 || (s1 + ',');
}
);
}
test(7456, "7,456");
test(45345, "45,345");
test(25.23523534, "25.23"); //truncated, not rounded
test(3333.239, "3,333.23"); //truncated, not rounded
test(234.99, "234.99");
test(2300.99, "2,300.99");
test(23123123123.22, "23,123,123,123.22");
function test(num, expected){
var actual = format(num);
console.log(num + ' -> ' + expected + ' => ' + actual + ': ' +
(actual === expected ? 'passed' : 'failed')
);
}
I added another layer where regex that drops the unwanted decimals below hundredths on top of your regex comma adding logic;
val.replace(/(\.\d{2})\d*/, "$1").replace(/(\d)(?=(\d{3})+\b)/g, "$1,")
doIt("7456");
doIt("45345");
doIt("25.23523534");
doIt("3333.239");
doIt("234.99");
doIt("2300.99");
doIt("23123123123.22");
doIt("5812090285.2817481974897");
function doIt(val) {
console.log(val + " -> " + val.replace(/(\.\d{2})\d*/, "$1").replace(/(\d)(?=(\d{3})+\b)/g, "$1,"));
}
If multiple calls of regex replace is OK, this answer should satisfy you, since it is only has regex replace logic and nothing else.
Try:
var n = 5812090285.2817481974897;
n = n.toFixed(2).replace(/(\d)(?=(\d{3})+\.)/g, '$1,');
console.log(n);
Outputs:
5,812,090,285.28
Note: .toFixed(2) returns a string. So in order to simplify this further you must add a way to turn n into a string before executing your regex. For example:
n.toString.replace(/(\d)(?=(\d{3})+\.)/g, '$1,'); //ofc with the additional regex
Although you would think it wouldn't matter in javascript, it apparently does in this situation. So I dont know how much 'less' messy it would be to not use.
Here is a way to do it without a regular expression:
value.toLocaleString("en-US", { maximumFractionDigits: 2 })
function formatValue() {
var source = document.getElementById("source");
var output = document.getElementById("output");
var value = parseFloat(source.value);
output.innerText = value.toLocaleString("en-US", { maximumFractionDigits: 2 });
}
<input id="source" type="text" />
<button onclick="formatValue()">Format</button>
<div id="output"></div>
RegEx to rescue again!
My solution has two parts :
.toFixed : Used to limit the decimal limit
/(\d)(?=(\d\d\d)+(?!\d))/g : It makes use of back reference with three digits at a time
Here's everything put together :
// .toFixed((/\./g.test(num)) ? 2 : 0) it tests if the input number has any decimal places, if so limits it to 2 digits and if not, get's rid of it altogether by setting it to 0
num.toFixed((/\./g.test(num)) ? 2 : 0).replace(/(\d)(?=(\d\d\d)+(?!\d))/g, "$1,"))
You can see it in action here :
var input = [7456, 45345, 25.23523534, 3333.239, 234.99, 2300.99, 23123123123.22]
input.forEach(function(num) {
$('div')
.append(
$('<p>').text(num + ' => ' +
num.toFixed( (/\./g.test(num))?2:0 ).replace(/(\d)(?=(\d\d\d)+(?!\d))/g, "$1,"))
);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div> </div>
NOTE: I've only used jQuery to append the results
You can do like this
(parseFloat(num).toFixed(2)).replace(/(\d)(?=(\d{3})+(?!\d))/g, "$1,").replace(".00","")
Here just convert number to formatted number with rounded down to 2 decimal places and then remove the .00 if exist.
This can be one approach you can use.
var format = function (num) {
return (parseFloat(num).toFixed(2)).replace(/(\d)(?=(\d{3})+(?!\d))/g, "$1,").replace(".00","")
}
$(function () {
$("#principalAmtOut").blur(function (e) {
$(this).val(format($(this).val()));
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input id="principalAmtOut" type="text" />
You can use Intl.NumberFormat with style set to "decimal" and maximumFractionDigits set to 2 at options object passed at second parameter
const nums = [7456, 45345, 25.23523534, 3333.239, 234.99, 2300.99, 23123123123.22];
const formatOptions = {style:"decimal", maximumFractionDigits:2};
const formatter = new Intl.NumberFormat("en-US", formatOptions);
const formatNums = num => formatter.format(num);
let formattedNums = nums.map(formatNums);
console.log(formattedNums);
I found a solution based on #Pierre's answer without using of toFixed:
function format(n) {
n = +n;
var d = Math.round(n * 100) % 100;
return (Math.floor(n) + '').replace(/(\d)(?=(\d{3})+$)/g, '$1,') + (d > 9 ? '.' + d : d > 0 ? '.0' + d : '');
}
console.log(format(7456));
console.log(format(7456.0));
console.log(format(7456.1));
console.log(format(7456.01));
console.log(format(7456.001));
console.log(format(45345));
console.log(format(25.23523534));
console.log(format(3333.239));
console.log(format(234.99));
console.log(format(2300.99));
console.log(format(23123123123.22));
console.log(format('23123123123.22'));
Currently this makes 11. It's for a slideshow and the var "n" equals 1 by default
function forward() {
document.getElementsByClassName("img")[0].setAttribute("class","imgout");
setTimeout( function() {
var n1 = document.getElementById("img").getAttribute("data-number");
var n=n1+1;
document.getElementById("img").setAttribute("data-number", n);
document.getElementById("img").setAttribute("src", "images/" + n + ".jpg");
document.getElementsByClassName("imgout")[0].setAttribute("class","img");
}, 500)
}
Use parseInt():
var n = parseInt(n1, 10) + 1;
Instead of:
var n=n1+1;
When n1 will be a string, because it came from the DOM, you need to convert n1 to an integer. There are many ways to do this, and really you should probably use a regular expression to validate that n1 contains what you expect first, but that being said you can try any of the following:
var n=parseInt(n1, 10)+1;
var n=(n1*1)+1;
var n=(+n1)+1;
As an aside the regex for validating the input from the DOM might be something such as:
/^-?\d+$/
Use Number():
var n = Number("1");
FIDDLE
parseInt - good choice. Also you can do
var n = n-0+1
Just remember that of you have different types "+" will convert to string and "-" will convert to numbers
Convert n1 to number as it is a string like ~~n1. The ~~n1 form is good if you know you want an integer (a 32-bit integer).
Second way is to use Number() function i.e. Number(n1) will convert n1 value into a string.
var n=parseInt(n)+1;
Documentation
Fiddle
I'm using a form that use the following script to calculate the item price including VAT:
function calculateTotaleIVA() {
var tot = document.getElementById('totale').value;
document.getElementById('totale_prodotto').value = Math.round(tot*121)/100;
totale_prodotto.value = document.getElementById('totale_prodotto').value.replace(".", ",");
totale.value = document.getElementById('totale').value.replace(".", ",");
}
This function works fine but I have a questions. Some times the result is like this:
46,4
I want to see at screen two digits after point decimal like this:
46,40
How can I fix the above function to solve it?
Thanks in advance.
Use toFixed
(Math.round(tot*121)/100).toFixed(2)
you can use toFixed(2) for that
toFixed(No of digits)
(Math.round(tot*121)/100).toFixed(2);
see here
I wanted to display a number to 2 decimal places.
I thought I could use toPrecision(2) in JavaScript .
However, if the number is 0.05, I get 0.0500. I'd rather it stay the same.
See it on JSbin.
What is the best way to do this?
I can think of coding a few solutions, but I'd imagine (I hope) something like this is built in?
float_num.toFixed(2);
Note:toFixed() will round or pad with zeros if necessary to meet the specified length.
You could do it with the toFixed function, but it's buggy in IE. If you want a reliable solution, look at my answer here.
number.parseFloat(2) works but it returns a string.
If you'd like to preserve it as a number type you can use:
Math.round(number * 100) / 100
Don't know how I got to this question, but even if it's many years since this has been asked, I would like to add a quick and simple method I follow and it has never let me down:
var num = response_from_a_function_or_something();
var fixedNum = parseFloat(num).toFixed( 2 );
with toFixed you can set length of decimal points like this:
let number = 6.1234
number.toFixed(2) // '6.12'
but toFixed returns a string and also if number doesn't have decimal point at all it will add redundant zeros.
let number = 6
number.toFixed(2) // '6.00'
to avoid this you have to convert the result to a number. you can do this with these two methods:
let number1 = 6
let number2 = 6.1234
// method 1
parseFloat(number1.toFixed(2)) // 6
parseFloat(number2.toFixed(2)) // 6.12
// method 2
+number1.toFixed(2) // 6
+number2.toFixed(2) // 6.12
Try toFixed instead of toPrecision.
function round(value, decimals) {
return Number(Math.round(value+'e'+decimals)+'e-'+decimals);
}
round(1.005, 2); // return 1.01
round(1.004, 2); // return 1 instead of 1.00
The answer is following this link: http://www.jacklmoore.com/notes/rounding-in-javascript/
I used this way if you need 2 digits and not string type.
const exFloat = 3.14159265359;
console.log(parseFloat(exFloat.toFixed(2)));
You could try mixing Number() and toFixed().
Have your target number converted to a nice string with X digits then convert the formated string to a number.
Number( (myVar).toFixed(2) )
See example below:
var myNumber = 5.01;
var multiplier = 5;
$('#actionButton').on('click', function() {
$('#message').text( myNumber * multiplier );
});
$('#actionButton2').on('click', function() {
$('#message').text( Number( (myNumber * multiplier).toFixed(2) ) );
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<button id="actionButton">Weird numbers</button>
<button id="actionButton2">Nice numbers</button>
<div id="message"></div>
The toFixed() method formats a number using fixed-point notation.
and here is the syntax
numObj.toFixed([digits])
digits argument is optional and by default is 0. And the return type is string not number. But you can convert it to number using
numObj.toFixed([digits]) * 1
It also can throws exceptions like TypeError, RangeError
Here is the full detail and compatibility in the browser.
let a = 0.0500
a.toFixed(2);
//output
0.05
There's also the Intl API to format decimals according to your locale value. This is important specially if the decimal separator isn't a dot "." but a comma "," instead, like it is the case in Germany.
Intl.NumberFormat('de-DE').formatToParts(0.05).reduce((acc, {value}) => acc += value, '');
Note that this will round to a maximum of 3 decimal places, just like the round() function suggested above in the default case. If you want to customize that behavior to specify the number of decimal places, there're options for minimum and maximum fraction digits:
Intl.NumberFormat('de-DE', {minimumFractionDigits: 3}).formatToParts(0.05)
float_num = parseFloat(float_num.toFixed(2))
I have made this function. It works fine but returns string.
function show_float_val(val,upto = 2){
var val = parseFloat(val);
return val.toFixed(upto);
}