I have a string "215.00".
I want to convert this to a number and when I do parseInt("215.00") it returns 215 as a number. I want it to be as a number 215.00.
To try and do this I did parseFloat("215.00").toFixed(2);, however this also returns a string. I have found many answers on here, but they all convert the number to a string. Does anyone know how to fix this?
Please see my code attempt below:
var number = "215.00";
parseFloat(number).toFixed(2);
I want to get 215.00 as opposed to "215.00"
I will post here this as an Answer, for future purpose.
If you want to represent the zeros on the right hand-side, you need to represent it as a string. Because the numerical value of 215.00 it is in fact 215, therefore it will not keep the two decimal places.
The parseFloat method would work for a number such as "215.01", where it would parse it to the numerical value of 215.01.
Related
I have a scenario where I need to parsefloat 19 digit string to number.
e.g. parseFloat("1000000000100000043") gives me 1000000000100000000
but the expected output required is 1000000000100000043
This is likely a precision overflow error.
The Number data type (but also int and float in other languages) have a finite number of bits available to represent a number. Typically around 15-16 decimal digits worth.
When length of original number in the string exceeds available precision, such number can no longer be represented by the target data type.
In this case the parseFloat function fails silently. If you want to catch this situation you need to add code to check incoming data or use another function, possibly a custom one.
Alternatively, you can convert the numeric value back to string and compare it with original to detect a discrepancy.
See also a question regarding double.Parse
You are running into how Javascript numbers are stored. See, e.g., here: https://www.w3schools.com/js/js_numbers.asp
You can use a library like decimal.js to work with large, exact numbers. These libraries store the number as string, but allow you to do mathematical operations.
Use
Hi, so I was working on my discord bot with some user ids that I stored in a database, which then I will get back to ping them or give them roles.
Problem
Though here's the problem, in the database they get turned from ex: 533692905387196429 to 533692905387196400. I tried setting that to a String, and it worked, in the database, it's stored fully how it's supposed to be. But, when I get them back from the database and turn them into a number or an integer they get turned back to ex: 533692905387196400.
Tried using
I tried using parseInt(), parseFloat() and Number() but all of them give the same result.
More info
Also if I remove 2 digits for example: 533692905387196429I remove 19 from there, it will give back 533692905387(19)6429 instead of 533692905387196429 and instead of 533692905387196400.
Any help is appreciated!
So, Number.MAX_SAFE_INTEGER is 9007199254740991 (which is 253 - 1). Your number is too large to hold full precision.
If you want a number with that level of digits and precision, you can use BigInt and then you will have to be very careful how you use that BigInt as it cannot be directly used in place of a regular Number type, but it can hold infinite precision and you can do math between two BigInt values.
Whether it's best used as a BigInt or as a String really depends upon what you're doing with it. If these are just some sort of ID that you aren't actually doing numeric operations with, then you can just keep it as a string.
The number is too big, so Javascript doesn't keep full precision!
> 533692905387196429
533692905387196400
You can resolve this by storing them as strings:
> '533692905387196429'
'533692905387196429'
You shouldn't need to do any mathematical operations with Discord IDs so there shouldn't be any issue storing and treating them as strings everywhere.
I have the problem that when i round a number to 2 decimals the parseFloat() function removes .00 from the number. I have tried
var num = parseFloat(Math.round(19 * 100) / 100).toFixed(2);
The return: num="19.00"
The return i need: num = 19.00
I know 19 = 19.00, but i am using a service that always require two decimals .00
The function returns a string with the right value. When i parse it to float the .00 is removed.
You cannot get 19.00 as float, only as string, because numbers always remove trailing zeros.
Maybe you can show us a bit more code to get an idea, there you need these trailing zeros?
Numbers do and can not hold information about their representation. They are only a numerical value.
When you display a number using window.alert, console.log or similar, you are not looking at a number, but at a string. Those display functions convert numbers to strings before displaying them. Number.toFixed also converts numbers into strings, with the difference being that it rounds them to two decimal places, so you end up with another representation of the same number.
What I am trying to say is that to display a number, you cannot get around converting it to a string. Whether you do it explicitly or the display function does it for you. When you send the number to the service that you are using, you are probably also sending a string (JSON, XML, etc. are always strings once you send them). If you need the value of the number for calculations, use it, then convert it in the end. No matter how, you have to do it in the end if you want those 0's at the end.
I have read some thousand comma separator JavaScript question/answer but found it hard to apply it in practice. For example I have the variable
x = 10023871234981029898198264897123897.231241235
How will I separate it in thousands with commas? I want a function that not only works with that number of digits but more. Regardless of the number of digits the function I need has to separate the number in commas and leaving the digits after the decimal point as it is, Can anyone help? It has to work on number and turn it into string.
First of all, for such huge numbers you should use string format:
var x = "10023871234981029898198264897123897.231241235";
Otherwise, JavaScript will automatically convert it to exponential notation, i.e. 1.002387123498103e+34.
Then, according to the question about money formatting, you can use the following code:
x.replace(/(\d)(?=(\d{3})+\.)/g, "$1,");
It will result in: "10,023,871,234,981,029,898,198,264,897,123,897.231241235".
I need to parse a json that contains a long number (that was produces in a java servlet). The problem is the long number gets rounded.
When this code is executed:
var s = '{"x":6855337641038665531}';
var obj = JSON.parse(s);
alert (obj.x);
the output is:
6855337641038666000
see an example here: http://jsfiddle.net/huqUh/
why is that, and how can I solve it?
As others have stated, this is because the number is too big. However, you can work around this limitation by sending the number as a string like so:
var s = '{"x":"6855337641038665531"}';
Then instead of using JSON.parse(), you can use a library such as javascript-bignum to work with the number.
It's too big of a number. JavaScript uses double-precision floats for numbers, and they have about 15 digits of precision (in base 10). The highest integer that JavaScript can reliably save is something like 251.
The solution is to use reasonable numbers. There is no real way to handle such large numbers.
The largest number JavaScript can handle without loss of precision is 9007199254740992.
I faced this issue some time ago, I was able to solve using this lib: https://github.com/josdejong/lossless-json
You can check this example:
let text = '{"normal":2.3,"long":123456789012345678901,"big":2.3e+500}';
// JSON.parse will lose some digits and a whole number:
console.log(JSON.stringify(JSON.parse(text)));
// '{"normal":2.3,"long":123456789012345680000,"big":null}' WHOOPS!!!
// LosslessJSON.parse will preserve big numbers:
console.log(LosslessJSON.stringify(LosslessJSON.parse(text)));
// '{"normal":2.3,"long":123456789012345678901,"big":2.3e+500}'