This question already has answers here:
Why JavaScript treats a number as octal if it has a leading zero
(3 answers)
Number with leading zero in JavaScript
(3 answers)
Closed 10 months ago.
I am working with an array of numbers
let nums = [02000, 02000, 02200, 02020,02002]
The problem is when I console.log(nums) it prints out [1024,1024,1152,1040,1026].
Why is it changing my numbers?
In JavaScript, Numeric Literals have their own lexical grammar.
When numbers start with a leading 0, it may be interpreted as an octal.
Note that decimal literals can start with a zero (0) followed by another decimal digit, but if all digits after the leading 0 are smaller than 8, the number is interpreted as an octal number.
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How to extract number from a string in javascript
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Get the first integers in a string with JavaScript
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How can I extract a number from a string in JavaScript?
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How to find a number in a string using JavaScript?
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Closed 2 years ago.
let string = "13th"
string = Number(string)
I expect it to return 13 instead I get NaN please how do I go about it
Try with parseInt()
If parseInt encounters a character that is not a numeral in the specified radix, it ignores it and all succeeding characters and returns the integer value parsed up to that point. parseInt truncates numbers to integer values. Leading and trailing spaces are allowed.
let string = "13th";
string = parseInt(string);
console.log(string);
This question already has answers here:
How do I include negative decimal numbers in this regular expression?
(17 answers)
Closed 3 years ago.
I am using the following to test for only numbers but I am having an issue with decimals still passing the test /^-{0,1}\d*\.{0,1}\d+$/.test(v) . Am I using this incorrectly to test for that?
if you want only integers, use:
/^-?\d+$/.test(v)
--- EXPLANATION
^ - start of the string
-? - minus in the start, ? means can be but not necessary
\d - any number (including zero)
+ - the last expression (=any number) can repeat more then once
$ - end of the string
This question already has answers here:
Javascript casts floating point numbers to integers without cause
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How to validate digits (including floats) in javascript
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Reference - What does this regex mean?
(1 answer)
Closed 4 years ago.
Any whole number ending in a dot returns the number in javascript console.(except decimal numbers)
like > 1. returns 1. Adding >1+1. also works. I don't understand why
typeof(1) // 'number'
typeof(1.) //'number'
However, when I put the same number inside a function, regex test gives a wrong output.
i.e,
const regex = /^\d+$/ //checks if there is a number inside a string
regex.test('1') // true
regex.test(1) //true
regex.test('1.') // false
The workaround I have is simply regex.test(Number('1.'))
JavaScript has a single type for all numbers: it treats all of them as floating-point numbers. However, the dot is not displayed if there are no digits after the decimal point:
5.000 = 5
Also, \d matches a digit, not a number.
This question already has answers here:
How do I work around JavaScript's parseInt octal behavior?
(10 answers)
Closed 7 years ago.
I have this code:
console.log(066); // 54
Why does it log 54, not 66?
In JavaScript, numeric literals that begin with a 0 are treated as octal.
From the MDN docs:
Octal number syntax uses a leading zero. If the digits after the 0 are outside the range 0 through 7, the number will be interpreted as a decimal number.
Because add a prefix 0 will make the number to be considered of base 8(octal), as way 0x will make the following number to be of base 16(hexa)
This question already has answers here:
How do I work around JavaScript's parseInt octal behavior?
(10 answers)
Closed 8 years ago.
So I saw this strange scenario. I wanted to convert a number to a String in Node.js and I got the following.
01010100132.toString()
Turns into
"136347738"
Can someone explain this to me?
Any numeric constant prefixed with a 0 is an octal literal (assuming all its digits are valid octal digits).
var i = 010; // 8 decimal