JavaScript Number parseInt() Method (original) (raw)
Last Updated : 31 May, 2024
The**parseInt method parses a value as a string and returns the first integer. It accepts a string argument and optional radix parameter, defining the numeral system base. This method is commonly used for converting string representations of numbers into integers.
**Example:
The method takes two parameters: the string to be parsed and the radix (optional, default is 10).
2 = binary, 8 = octal, 10 = decimal, 16 = hexadecimal.
**Syntax
parseInt(Value, radix);
**Parameters
- **Value: This parameter contains a string that is converted to an integer.
- **radix: This parameter represents the radix or base to be used and it is optional.
**Return value
It returns a number and if the first character can’t be converted to a number then the function returns NaN. It returns a number parsed up to that point where it encounters a character that is not a number in the specified radix(base).
**Example 1: Parsing float value
Here, we are using the parseInt() method to parse the given float value.
javascript `
let v1 = parseInt("3.14"); console.log('Using parseInt("3.14") = '+ v1);
`
Output
Using parseInt("3.14") = 3
**Example 2: Parsing value with given radix
**Here, we will also mention radix with the number.
javascript `
// Base 10 a = parseInt("100", 10); console.log('parseInt("100",10) = ' + a);
// Base 8 b = parseInt("8", 8); console.log('parseInt("8",8) = ' + b);
// Base 8 c = parseInt("15", 8); console.log('parseInt("15",8) = ' + c);
// Base 16 d = parseInt("16", 16); console.log('parseInt("16",16) = ' + d);
// Leading and trailing spaces are ignored // in parseInt() function e = parseInt(" 100 "); console.log('parseInt(" 100 ") = ' + e);
// Base 16(hexadecimal) f = parseInt("0x16"); console.log('parseInt("0x16") = ' + f);
`
Output
parseInt("100",10) = 100 parseInt("8",8) = NaN parseInt("15",8) = 13 parseInt("16",16) = 22 parseInt(" 100 ") = 100 parseInt("0x16") = 22
We have a complete list of JavaScript Number constructor, properties, and methods list, to know more about the numbers please go through that article.