Which one to use when? When? Why? This tip is an analysis of each one and it's common pitfalls.Īccording to a couple benchmarks in most browsers have optimal response for ParseInt. ParseInt(num, 10) // parseInt with radix (decimal) I can think of at least 5 ways to convert a string into a number! parseInt(num) // default way (no radix) I share all new blog posts on Twitter and Facebook.There are many ways to convert a String to a Number. Search fiverr to find help quickly from experienced Vanilla JS freelance developers. Set('parseFloat3', parseFloat('123abc')) ĭocument.getElementById(id).innerHTML = value
#Convert to number javascript code#
This is the JavaScript code running in the above example. Here they are in action: (Edit on StackBlitz at ) It returns NaN (Not a Number) if the input value doesn't represent a number, and like Number() it returns zero ( 0) for an empty string ( Math.floor('')). The Math.floor() method accepts a string parameter and converts it to an integer that is rounded down to the lowest whole number, for example '12.9' is converted to 12. It returns NaN (Not a Number) if the input value doesn't represent a number, and like Number() it returns zero ( 0) for an empty string ( Math.round('')). The Math.round() method accepts a string parameter and converts it to an integer that is rounded to the closest whole number, for example '12.4' is converted to 12 and '12.5' is converted to 13. Like the Number() function, it returns zero ( 0) for an empty string ( '' * 1).
#Convert to number javascript plus#
Multiplying a string by 1 ( * 1) works just like the unary plus operator above, it converts the string to an integer or floating point number, or returns NaN (Not a Number) if the input value doesn't represent a number. Like the Number() function, it returns zero ( 0) for an empty string ( +''). The unary plus operator ( +) placed before a string converts it to an integer or floating point number, or returns NaN (Not a Number) if the input value doesn't represent a number. If the input is an empty string ( Number('')) then NaN (Not a Number) is returned. '123abc') then parseInt() will return the number from the beginning of the string (e.g. If the input string begins with a number (e.g. The parseFloat() function accepts a string parameter and converts it to an floating point number (with a decimal point if required), or returns NaN (Not a Number) if the input value doesn't represent a number. The parseInt() function accepts a string parameter and converts it to an integer number, or returns NaN (Not a Number) if the input value doesn't represent a number. The way to check if a value equals NaN is to use the isNan() function. An interesting thing to note is that zero ( 0) is returned for an empty string ( Number('')). The Number() function accepts a string parameter and converts it to an integer or floating point number, or returns NaN (Not a Number) if the input value doesn't represent a number.
This is a quick post to show examples of 7 different ways to convert a string to a number in JavaScript along with the output that each gives for different values.
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