This question already has answers here:
What is JavaScript's highest integer value that a number can go to without losing precision?
(21 answers)
Closed 8 years ago.
Can anybody solve the following problem with javascript
var i = 10152233307863175;
alert(i.toString());
alert shows value 10152233307863176. Any solution. Problem is when I get json object on client and when string is converted to json it contains wrong values.
This is a limitation in the precision of the numeric data format that javascript uses (double precision floating point).
The best way of storing that value, assuming you don't need to do any mathematical operations, is storing it as a string in the first place.
MDN has this to say about numbers in JavaScript.
Numbers in JavaScript are "double-precision 64-bit format IEEE 754 values", according to the spec.
There is no real integers in JavaScript. According to this source:
ECMAScript numbers are represented in binary as IEEE-754 (IEC 559) Doubles, with a resolution of 53 bits, giving an accuracy of 15-16 decimal digits; integers up to just over 9e15 are precise, ...
Your number 10152233307863175 contains 17 digits. Since the number is represented as a floating point number, JavaScript tries to do it's best and set bits in a way that the resulting number is closest to the supplied number.
Related
This question already has answers here:
What is JavaScript's highest integer value that a number can go to without losing precision?
(21 answers)
Closed 4 months ago.
How to increase this number(you can try it on the browser console):
36893488147419103000 + 1
The result of this is:
36893488147419103000
The number stays the same no changes to it why is that? and how can I increase it by 1?
For big integers you should use the BigInt (Big Integer) type.
Note 1: you almost always cannot mix BigInt numbers with Numbers (eg for math operations) without first performing an explicit conversion.
Note 2: JSON does not currently natively support BigInt values. As a workaround you can use strings (eg. '1n' for the values and then use a reviver function when calling JSON.parse.
JavaScript currently only has two numeric types: double-precision IEEE 754 floating point Numbers, and Big Integers which can be used to represent arbitrarily large integers. You can declare a BigInt number literal using the suffix n, eg. 1n.
IEEE 754 Numbers can "only" accurately represent integers up to and including Number.MAX_SAFE_INTEGER, which has a value of 2^53 - 1 or 9,007,199,254,740,991 or ~9 quadrillion.
From MDN:
Double precision floating point format only has 52 bits to represent the mantissa, so it can only safely represent integers between -(253 – 1) and 253 – 1. "Safe" in this context refers to the ability to represent integers exactly and to compare them correctly. For example, Number.MAX_SAFE_INTEGER + 1 === Number.MAX_SAFE_INTEGER + 2 will evaluate to true, which is mathematically incorrect. See Number.isSafeInteger() for more information.
A "Decimal" number type, that will be able to represent arbitrarily precise decimal numbers, is under development.
Obviously the number is internally represented as a floating point number.When the value you want do add to this number is less then the value of the least significant bit, it will not change the the value.
The only way would be to use floating point numbers with a higher resolution i.e. with a higher number of significant bits.
Double precision floating point format only has 52 bits to represent the mantissa, so it can only safely represent integers between -(253 – 1) and 253 – 1. See Number.MAX_SAFE_INTEGER. Larger numbers may not be able to be represented exactly.
This question already has answers here:
How to avoid scientific notation for large numbers in JavaScript?
(27 answers)
Closed 6 years ago.
I try to get
Math.pow(2,1000);
The result is " 1.2676506002282294e+30 "
I need the number without Euler's number "e+30"
That's scientific notation, not Euler's number.
If you want to show the number without the e+NN part:
convert it to a string
parse the e+NN part
shift the decimal place the appropriate number of digits
return the output as a string
be aware that doing so will lead to inaccurate values for some calculations due to how floating point arithmetic works.
With very large numbers, JavaScript displays them in scientific notation. This is because it is very expensive and unreadable to list them.
For your example, it basically means
1.2676506002282294 * 10 ^ 30
You take the number and then multiply it by 10 to the 30th power.
Calculators often use "E" or "e" like this: 1.8004E+94
6E+5 is the same as 6 × 10^5
To get it without this notation, simply use smaller numbers as the exponent.
Example: Math.pow(2,10)
Mathisfun provides an excellent article on scientific notation. Check it out here
https://www.mathsisfun.com/numbers/scientific-notation.html
Euler's number is a constant that is the base of a natural number. It's an irrational number, meaning its digits go on forever. The first couple digits are 2.7182818284
This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 7 years ago.
Today I have entered random float number and multipled by hundred firstly using normal code and then in console as was giving me wrong number, console is returning me the same.
The given float number is: 1050.6
Therefore: 1050.6 * 100 should be 105060, but javascript is returning me 105059.99999999999
Anyone knows why?
JavaScript uses 64-bit floating point representation (double precision). Numbers are represented in this format as a whole number multiplied by a power of two.
This is based on the IEEE 754 standard
Rational numbers with a denominator that isn't a power of 2 can't be exactly represented. This is why floating point multiplication gives this result.
Source: https://en.wikipedia.org/wiki/IEEE_floating_point
If you want to get the real value, there are two methods you can use
Rounding with Math.round
Math.round(1050.6 * 100)
Or toFixed
(1050.6 * 1000).toFixed(0)
It's a feature of how computers handle floating point numbers. It turns out that decimal numbers can't always be perfectly represented in binary so the computer gives the closest approximation it can.
https://en.wikipedia.org/wiki/IEEE_floating_point
This question already has answers here:
Javascript toFixed function
(6 answers)
Closed 8 years ago.
When the non fractional part is bigger than 4 the fractional part it is truncated to .3 but when it is smaller than 4 it is rounded to .4.
Examples:
1.nr>4:
5.35.toFixed(1) => 5.3
15.35.toFixed(1) => 15.3
131.35.toFixed(1) => 131.3
2.nr<4:
2.35.toFixed(1) =>2.4
1.35.toFixed(1) =>1.4
Is this kind of behaviour normal?
The problem is that the exact values you're calling toFixed on aren't 1.35 etc... they're the nearest IEEE-754 64-bit representation. In this case, the exact values are:
1.350000000000000088817841970012523233890533447265625
2.350000000000000088817841970012523233890533447265625
5.3499999999999996447286321199499070644378662109375
15.3499999999999996447286321199499070644378662109375
Now look at those values and work out what you'd do in terms of rounding to 1 decimal place.
Basically you're falling foul of the fact that these are floating binary point values, so the value you express in decimal isn't always the value that's actually used. It's just an approximation. In other languages the preferred alternative is to use a type which represents floating decimal point values (e.g. BigDecimal in Java or decimal in C#) but I don't know of anything similar within standard Javascript. You may find some third party libraries though.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Large numbers erroneously rounded in Javascript
I am experiencing some strange behavior when working with numbers in javascript. When I use the following code:
CLICK HERE
I get the number 9200000000032336 in my console. I think it most be something with rounding or max values for numbers, but I don't understand it completely. Anyone?
I'm not a Javascript expert, but it sounds like your number is being stored as an IEEE-754 64-bit floating point number. Certainly that's what I get from C# code which will display the exact value of a double:
double d = 9200000000032337;
Console.WriteLine(DoubleConverter.ToExactString(d));
(Using my own DoubleConverter class.) My output is the same as yours: 9200000000032336
Floating point values only ever hold a certain number of significant digits accurately - and when the numbers get high enough, even integers can't be stored exactly.
ECMA-262 seems to confirm this:
4.3.19
Number value
primitive value corresponding to a double-precision 64-bit binary format IEEE 754 value
and from section 7.8.3 (numeric literals):
A numeric literal stands for a value of the Number type. This value is determined in two steps: first, a
mathematical value (MV) is derived from the literal; second, this mathematical value is rounded as described
below.
Section 8.5 contains more details.