如何在Java中删除小数部分的“ 0”？

Question

I have a float value of a current weight like eg "79.3" kilograms. I split the float value into a kilogram and a grams value.

I get the right amount of kilograms when parsing the float-value to int. Then I get the fractional part of the float-value. This fractional part looks like "0,3" which means 0.3 kilograms or 300grams. In my Programm I can only have 0,100,200,..,900 Grams which would stand for 0-9. My goal is to remove the "0," so I only get the value of "3".

This is my code for now and I tried some decimal formatting too, but I didn't know how to do it:

public void setCurrentWeightInTheNumberPickers() {
    float currentWeightAsFloat = weight_dbHandler.getCurrentWeightFloat();
    int currentWeightKilograms = (int) currentWeightAsFloat;
    double fractionOfGrams = currentWeightAsFloat % 1;
    DecimalFormat df1 = new DecimalFormat("0.##");
    String rounded = df1.format(fractionOfGrams);
    rounded.replaceFirst("^0+(?!$)", "");

} //public void setCurrentWeightInTheNumberPickers()

Answer 1

Given a string

String gram = "0,3";

you can just do:

gram = gram.substring(gram.lastIndexOf(",") + 1);

which gives the following output when printed

3

Answer 2

I view this primarily as a math, not a Java, problem. Given a float input in units of kilograms, to obtain only the kilogram component, we can take the floor. To get the grams component, we can multiply by 1000 and then take the mod of 1000.

double input = 79.321;
double kg = Math.floor(input);
System.out.println("kilograms: " + kg);
double g = Math.floor((1000*input) % 1000);
System.out.println("grams: " + g);

kilograms: 79.0
grams: 321.0

Note: I am using double here instead of float , only because Math.floor returns double as its return value.

Answer 3

Or you can simply do that. No need for strings.

float f = 3.3f;
int g = (int)f;
int h = Math.round((f - g)*10);

and since h is supposed to be grams, you might as well make it *1000