Javascript Challenge 14 – Datatype number and parseFloat

Today we are going to talk about two important concepts in Javascript – datatype number and parseFloat.

The datatype number in Javascript is used to represent numeric data. It can hold both positive and negative numbers, as well as decimal numbers. In Javascript, numbers are stored as 64-bit floating point numbers, which means they can accurately represent integers up to 2^53 and fractions to a certain precision.

When working with user input, it’s important to be able to convert a string to a number. This is where the parseFloat function comes in. The parseFloat function takes a string as input and returns a floating point number. It first parses the string until it reaches a non-numeric character, and then returns the number up to that point. This means that if you have a string that starts with a number but contains non-numeric characters afterwards, the parseFloat function will still return the valid number at the beginning of the string.

Here’s an example of how you can use the parseFloat function:

var str = "3.14 is the value of PI";
var num = parseFloat(str);
console.log(num); // Output: 3.14

As you can see, the parseFloat function correctly parses the string and returns the valid number at the beginning.

It’s important to note that if the string does not start with a valid number, the parseFloat function will return NaN (Not a Number). This can be useful for error checking when dealing with user input.

In conclusion, understanding the datatype number and the parseFloat function is essential when working with numeric data in Javascript. They allow you to accurately represent and manipulate numbers, as well as parse strings to extract numeric values. By mastering these concepts, you can improve your ability to work with numerical data in Javascript.