java : convert float to String and String to float

Question

How could I convert from float to string or string to float?

In my case I need to make the assertion between 2 values string (value that I have got from table) and float value that I have calculated.

String valueFromTable = "25";
Float valueCalculated =25.0;

I tried from float to string:

String sSelectivityRate = String.valueOf(valueCalculated );

but the assertion fails

Answer 1

You can try this sample of code:

public class StringToFloat
{

  public static void main (String[] args)
  {

    // String s = "fred";    // do this if you want an exception

    String s = "100.00";

    try
    {
      float f = Float.valueOf(s.trim()).floatValue();
      System.out.println("float f = " + f);
    }
    catch (NumberFormatException nfe)
    {
      System.out.println("NumberFormatException: " + nfe.getMessage());
    }
  }
}

found here

Answer 2

well this method is not a good one, but easy and not suggested. Maybe i should say this is the least effective method and the worse coding practice but, fun to use,

float val=10.0;
String str=val+"";

the empty quotes, add a null string to the variable str, upcasting 'val' to the string type.

Answer 3

Float to string - String.valueOf()

float amount=100.00f;
String strAmount=String.valueOf(amount);
// or  Float.toString(float)

String to Float - Float.parseFloat()

String strAmount="100.20";
float amount=Float.parseFloat(strAmount)
// or  Float.valueOf(string)

Answer 4

This is a possible answer, this will also give the precise data, just need to change the decimal point in the required form.

public class TestStandAlone {

    /**
     * 
This method is to  main
     * @param args  void
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        try {
            Float f1=152.32f;
            BigDecimal roundfinalPrice = new BigDecimal(f1.floatValue()).setScale(2,BigDecimal.ROUND_HALF_UP);

            System.out.println("f1 --> "+f1);
            String s1=roundfinalPrice.toPlainString();
            System.out.println("s1 "+s1);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

Output will be

f1 --> 152.32
s1 152.32

Answer 5

String str = "1234.56";
float num = 0.0f;

int digits = str.length()- str.indexOf('.') - 1;

float factor = 1f;

for(int i=0;i<digits;i++) factor /= 10;

for(int i=str.length()-1;i>=0;i--){

    if(str.charAt(i) == '.'){
        factor = 1;
        System.out.println("Reset, value="+num);
        continue;
    }

    num += (str.charAt(i) - '0') * factor;
    factor *= 10;
}

System.out.println(num);

Answer 6

Using Java’s Float class.

float f = Float.parseFloat("25");
String s = Float.toString(25.0f);

To compare it's always better to convert the string to float and compare as two floats. This is because for one float number there are multiple string representations, which are different when compared as strings (e.g. "25" != "25.0" != "25.00" etc.)