JavaScript Number parseInt() Method
Last Updated :
05 Mar, 2024
The parseInt() method in JavaScript converts a string into an integer (a whole number) based on the specified radix (base). If the first character of the string cannot be converted to a number, NaN is returned.
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.
Number parseInt() Method Syntax
parseInt(Value, radix);
Number parseInt() Method 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.
Number parseInt() Method 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).
Number parseInt() Method Examples
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
Explanation
- In the above example we parseInt(“3.14”) converts the string “3.14” to an integer.
- Since “3.14” is parsed, only the integer part (3) is considered.
- The value of v1 will be 3, not 3.14.
Example 2: Parsing value with given radix
Here, we will also mention radix with the number.
javascript
a = parseInt("100", 10);
console.log('parseInt("100",10) = ' +
a);
b = parseInt("8", 8);
console.log('parseInt("8",8) = ' +
b);
c = parseInt("15", 8);
console.log('parseInt("15",8) = ' +
c);
d = parseInt("16", 16);
console.log('parseInt("16",16) = ' +
d);
e = parseInt(" 100 ");
console.log('parseInt(" 100 ") = ' +
e);
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
Explanation:
The code demonstrates the parseInt() method with different radix values and string formats:
"100" parsed in base 10 yields 100."8" parsed in base 8 yields 8."15" parsed in base 8 (treated as octal) yields 13."16" parsed in base 16 (hexadecimal) yields 22.- Leading and trailing spaces are ignored;
" 100 " yields 100.
"0x16" is treated as hexadecimal and yields 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.
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