convert string to number javascript isnan

Convert string to number javascript isnan how to#

Similar to the + unary operator, but returns the integer part, is to use Math.floor(): Math. See how it returns NaN in the first example, which is the correct behavior: it’s not a number. Its parseInt() sibling, it only takes one argument – the string to convert: parseFloat ( '10,000' ) //10 ❌ parseFloat ( '10.00' ) //10 ✅ (considered decimals, cut) parseFloat ( '10.000' ) //10 ✅ (considered decimals, cut) parseFloat ( '10.20' ) //10.2 ✅ (considered decimals) parseFloat ( '10.81' ) //10.81 ✅ (considered decimals) parseFloat ( '10000' ) //10000 ✅ Use + If you want to retain the decimal part and not just get the integer part, use parseFloat(). ParseInt() tries to get a number from a string that does not only contain a number: parseInt ( '10 lions', 10 ) //10īut if the string does not start with a number, you’ll get NaN (Not a Number): parseInt ( 'I'm 10', 10 ) //NaNĪlso, just like Number it’s not reliable with separators between the digits: parseInt ( '10,000', 10 ) //10 ❌ parseInt ( '10.00', 10 ) //10 ✅ (considered decimals, cut) parseInt ( '10.000', 10 ) //10 ✅ (considered decimals, cut) parseInt ( '10.20', 10 ) //10 ✅ (considered decimals, cut) parseInt ( '10.81', 10 ) //10 ✅ (considered decimals, cut) parseInt ( '10000', 10 ) //10000 ✅ Other solutions Use parseInt() and parseFloat()Īnother good solution for integers is to call the parseInt() function: const count = parseInt ( '1234', 10 ) //1234ĭon’t forget the second parameter, which is the radix, always 10 for decimal numbers, or the conversion might try to guess the radix and give unexpected results. In the case you need to parse a string with decimal separators, use Intl.NumberFormat instead. If we use the constructor ( new Number('1234')) it returns us a Number object instead of a number value, so pay attention. Number is a wrapper object that can perform many operations. The best one in my opinion is to use the Number object, in a non-constructor context (without the new keyword): const count = Number ( '1234' ) //1234 JavaScript provides various ways to convert a string value into a number.

Convert string to number javascript isnan how to#

Learn how to convert a string to a number using JavaScript