Remove leading zeros from a number in Javascript

Question

Possible Duplicate    Truncate leading zeros of a string in Javascript       What is the simplest and cross-browser compatible way to remove leading zeros from a number in Javascript    e g  If I have a textbox value as 014 or 065  it should only return 14 or 65

User · Accepted Answer

We can use four methods for this conversion

parseInt with radix 10
Number Constructor
Unary Plus Operator
Using mathematical functions (subtraction)

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const numString = "065";_x000D_
_x000D_
//parseInt with radix=10_x000D_
let number = parseInt(numString, 10);_x000D_
console.log(number);_x000D_
_x000D_
// Number constructor_x000D_
number = Number(numString);_x000D_
console.log(number);_x000D_
_x000D_
// unary plus operator_x000D_
number = +numString;_x000D_
console.log(number);_x000D_
_x000D_
// conversion using mathematical function (subtraction)_x000D_
number = numString - 0;_x000D_
console.log(number);

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Update(based on comments): Why doesn't this work on "large numbers"?

For the primitive type Number, the safest max value is 2^53-1(Number.MAX_SAFE_INTEGER).

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console.log(Number.MAX_SAFE_INTEGER);

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Now, lets consider the number string '099999999999999999999' and try to convert it using the above methods

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const numString = '099999999999999999999';_x000D_
_x000D_
let parsedNumber = parseInt(numString, 10);_x000D_
console.log(`parseInt(radix=10) result: ${parsedNumber}`);_x000D_
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parsedNumber = Number(numString);_x000D_
console.log(`Number conversion result: ${parsedNumber}`);_x000D_
_x000D_
parsedNumber = +numString;_x000D_
console.log(`Appending Unary plus operator result: ${parsedNumber}`);_x000D_
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parsedNumber = numString - 0;_x000D_
console.log(`Subtracting zero conversion result: ${parsedNumber}`);

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All results will be incorrect.

That's because, when converted, the numString value is greater than Number.MAX_SAFE_INTEGER. i.e.,

99999999999999999999 > 9007199254740991

This means all operation performed with the assumption that the stringcan be converted to number type fails.

For numbers greater than 2⁵³, primitive BigInt has been added recently. Check browser compatibility of BigInthere.

The conversion code will be like this.

const numString = '099999999999999999999';
const number = BigInt(numString);

P.S: Why radix is important for `parseInt`?

If radix is undefined or 0 (or absent), JavaScript assumes the following:

If the input string begins with "0x" or "0X", radix is 16 (hexadecimal) and the remainder of the string is parsed
If the input string begins with "0", radix is eight (octal) or 10 (decimal)
If the input string begins with any other value, the radix is 10 (decimal)

Exactly which radix is chosen is implementation-dependent. ECMAScript 5 specifies that 10 (decimal) is used, but not all browsers support this yet.

For this reason, always specify a radix when using parseInt

User · Answer

It is not clear why you want to do this  If you want to get the correct numerical value  you could use unary    docs    value    value    If you just want to format the text  then regex could be better  It depends on the values you are dealing with I d say  If you only have integers  then   input value    input value    is fine as well  Of course it also works for float values  but depending on how many digits you have after the point  converting it to a number and back to a string could  at least for displaying  remove some

User · Answer

regexp    014  replace   0

[javascript] Remove leading zeros from a number in Javascript

Update(based on comments): Why doesn't this work on "large numbers"?

P.S: Why radix is important for `parseInt`?

Examples related to javascript

Examples related to html

Examples related to parseint

[javascript] Remove leading zeros from a number in Javascript

Update(based on comments): Why doesn't this work on "large numbers"?

P.S: Why radix is important for parseInt?

Examples related to javascript

Examples related to html

Examples related to parseint

P.S: Why radix is important for `parseInt`?