How to convert JavaScript string to number

How can I convert a string to a number?

parseInt, parseFloatand Numberthe constructor.

How to convert a string to a number using “parseInt” and “parseFloat”

The Number functions parseInt and parseFloat can be used to convert strings to numbers.

These parse strings and convert them to numbers. The difference is that each can handle integers and floating point numbers.

How to use parseInt

To convert a string to an integer number, parseIntyou can use a function.

How to use it is as follows.

const str = '123';
const num = parseInt(str);
console.log(typeof num); // -> 'number'

parseIntThe second argument of the function allows you to specify the radix to use when parsing the string. For example, to parse a binary string, specify 2 as the second argument.

const str = '1101';
const num = parseInt(str, 2);
console.log(num); // -> 13

How to use parseFloat

To convert a string to a number with a decimal point, parseFloatyou can use a function.

How to use it is as follows.

const str = '123.45';
const num = parseFloat(str);
console.log(typeof num); // -> 'number'

The parseFloat function can also convert an integer to a number with a decimal point.

const str = '123';
const num = parseFloat(str);
console.log(typeof num); // -> 'number'

Using the “Number” function

To convert a string to a number, you can also use the Number function.

The usage is as follows.

const str = '123';
const num = Number(str);
console.log(num); // -> 123

const str2 = '123abc';
const num2 = Number(str2);
console.log(num2); // -> NaN

Number conversion returns NaN (Not a Number) in case of confusion of strings, etc.

summary

The following is a summary of how to convert a string to a number .

It is important to choose which method to use depending on the purpose and string used!

It is also important to note that attempting to convert a non-numeric string NaNwill return .