String decimal to percentage in java [duplicate]

Question

I have a string value as below:

String percValue = "0.0209"

How can I convert this to something like as below

String formatedValue = "2.09%";

Can someone help me what is the simple and best way to convert this?

Answer 1

One good way would be to:

• convert your percentage string to a number (needs to be a double type variable, so it can hold the decimal places...),
• multiply the value by 100 to make it a percentage,
• re-format the number in a string.

String percValue = "0.0209";
double percentage = Double.parseDouble(percValue) * 100;
String formattedValue = String.format("%.2f%%", percentage);

Explanation:

• Double.parseDouble() takes your string as a parameter and returns a double value which you can do things like multiplication and addition with, and
• String.format() lets you precisely control how your number is converted back to a String!
• "%.2f" means "Take the next argument which is a floating-point variable and put it here, with two decimal places".
• "%%" means "print a single '%'". You need two to "escape" it, since percent symbols are not literally interpreted in format strings.