Convert an entire number to a float with decimals

Question

Convert an entire number to a float with decimals

Asked 6 years, 6 months ago

Viewed 996 times

1

How can I turn a number:

5 in: 0,0005

10 in: 0,0010

I’m trying this way:

int numero = 5;
float numero2 = Math.abs(numero / 10000);

But it’s returning to me like this: 0.0

Just divide by 1000, no?

– Felipe Avelar

2017/12/21 at 17:18
Yes, as is the method itself?

– user92401

2017/12/21 at 17:18
Just split normally... var/1000

– Felipe Avelar

2017/12/21 at 17:19
Ok, and how can I do with INT values of a column? Even if I put double in the method it returns me only 0,0 and the value in the column is 5

– user92401

2017/12/21 at 17:21
Provide a [mcve] of your code, otherwise you will only get guesses.

– user28595

2017/12/21 at 17:24
The problem is that you are declaring as Int and Integer does not accept numbers after the comma, try using float type

– Felipe Avelar

2017/12/21 at 17:25
Ready I edited..

– user92401

2017/12/21 at 17:29
Math.abs(numero / 10000f);

– user28595

2017/12/21 at 17:29
Call me back 5.0E-4

– user92401

2017/12/21 at 17:31
This result is right, this is scientific notation. 5.0E-4 is the same as 5.0 * 10^-4, which results in the value you want. If you want the numeral without notation, you need to use another type of data, such as Biginteger.

– user28595

2017/12/21 at 17:39
Okay, and how would you look with Biginteger?

– user92401

2017/12/21 at 17:43

Show 6 more comments

1 answer

Browser other questions tagged java

You are not signed in. Login or sign up in order to post.

by Woss • **73,416** points · Answer 1 · 2017-12-21T18:40:58+00:00

This is nothing more than a peculiarity of Java. When you display a value on the screen, implicitly it is called the method toString of the object. In documentation of this method there is the comment that when the magnitude of the value is less than 10 -3 or more than 10 7 the value will be displayed with scientific notation. This probably is to make your representation more readable to humans, since it does not change the execution of the code at all (the value does not change).

In the documentation of System.out.println(float) it is said that his execution is a call to System.out.print(float) followed by a System.out.println(). In turn, the method System.out.print(float) displays the value returned by String.valueOf(float), that returns exactly the value returned by Float.toString. Already in the method documentation System.out.printf there is that the return will be the same as System.out.format, which displays the values according to the rules defined for the Formatter, where f is the format for a decimal value, without invoking the method toString.

As the result of the expression is less than 10 -3, it is presented as scientific notation, leaving 5.0E-4, which is the equivalent of 0.0005.

If you really want to display the value without scientific notation, you can display the value using the method printf, in place of println, defining the format %f:

float numero = 5;
float numero2 = numero / 10000;
System.out.printf("%f\n", numero2);  // 0.000500

^{See working on Repl.it}