Javascript convert decimal power to regular decimal

Question

Using Javascript Math I can convert a decimal number like 100 into decimal power number like 1e+2

Math.pow(10, 2)

But how can I do it the other way round? How can I convert a decimal power like 1e+2 to a regular decimal like 100? I need this to save a number in a database number column. I could not find any method or jquery plugin that will do this for me.

Answer 1

The expression you showed above, Math.pow(10, 2) , actually evaluates to 100 .

But if you are given the string 1e+2 , you can change it into 100 by calling parseFloat() :

 var s = '1e+2', // This is a string in scientific notation. x = parseFloat(s); // Here we convert it to the more widespread notation. document.write('"'+s+'" -> '+x); // Let's print out the values for testing purposes. 

Answer 2

What you are talking about is number formats, not numbers.

The string "100" is the textual representation of the number 100 . The string "1e+2" is the textual representation of the same number, but in scientific format.

A numeric value doesn't have any specific format. The values in the variables a , b and c in this code are completely identical:

var a = 100;
var b = Math.pow(10, 2);
var c = 1e+2;

A numeric value only gets a specific format when you create a textual represenation of the number. I this code the variables from the previous example are displayed as text:

console.log(a);
console.log(b);
console.log(c);

As the values are not to small or too large to be resonably represented in the regular decimal format, that's how they come out:

100
100
100

When you want to store a numeric value in the database, it doesn't matter where the number came from, it's just the numeric value itself that is used.

Answer 3

Math.pow(x, y) actually returns the result of x^y. In your specific case, it is being represented in scientific notation, but the actual number is still being 100. If you have a string and want to get the actual number, you can use:

Number("1e+2")

Example

 $("#result").append(Number("1e+2")); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <div id="result"></div>