Convert Array to Floats Array with notation Java

Question

Sorry for the title name but this is probably a funny question. i need to have this like it is. I have an array of floats in the format [10.0, 20.0, 30.0, 40.0, 50.0] i need the array to be represented like [10.0f, 20.0f, 30.0f, 40.0f, 50.0f] . I have tried using array List to convert and add the notation and convert back.. but no matter what i try, i still get a float array that looks like a double. Any ideas Please?

even tried something like this:

ArrayList<String> valuelist = new ArrayList<String>();
for(int z = 0; z < mValues.length; z++){
    valuelist.add(Float.toString(mValues[z]) + "f");
}  //its fine here but later changes

Object[] objarray2 = valuelist.toArray();
String[] stringfloat  = Arrays.copyOf(objarray2, objarray2.length, String[].class);              
float[] myfloat = new float[stringfloat.length];
for(int j =0; j< myfloat.length; j++){
    //myfloat[j] = Float.parseFloat(stringfloat[j]);
    myfloat[j] = Float.valueOf(stringfloat[j]);
}

Answer 1

f is used to tell the compiler that treat this as float number. If you want your array in this format use an array of string and append f in each element

As per JLS :

A floating-point literal is of type float if it is suffixed with an ASCII letter F or f ; otherwise its type is double and it can optionally be suffixed with an ASCII letter D or d (§4.2.3).

Answer 2

Keep the original array where members are float and just create a "String myToString()" method to print it like you want, with the +"f". I mean, create a personalized method to print the array like you want it to appear.

I assume you just want the print out of the array of float to "appear" with a final f. The representation in the machine of the number will not change with an f at the end or not. The final f in the string is useful when parsing a number, so you the parser knows which kind of number it is, if you already do not tell it.

Answer 3

You have:

myfloat[j] = Float.valueOf(stringfloat[j]);

Here's Float.valueOf(String) :

public static Float valueOf(String s) throws NumberFormatException 
{
    return new Float(FloatingDecimal.readJavaFormatString(s).floatValue())
}

As you can see, it returns a Float , which is created through Float(float) constructor, which is simply:

public Float(double value) 
{
   this.value = (float) value;
}

The readJavaFormatString(String) converts the String to a double , and .floatValue() converts the double , wrapped in a FloatingDecimal to a float , which is passed to the above constructor. So, im short, you do have a float .

NB:

float num1 = XYZ;
float num2 = XYZf;

Despite the different notation, num1 and num2 compile to the same bytecode (where XYZ are some numbers, say 123); however, you cannot make an assignment of a number ending in an f to say an int . Additionally, if you try to put an int into a float, you do not need the f at the end, but if your number has any numbers to the right of the radix, you need to append the f so that it will compile with a possible loss of precision error.

Also, you really shouldn't be using float unless there's a good reason to do so, especially if you're planning to use == for comparison; instead, use double . float and double are essentially the same thing, except that double is 64-bits, whereas a float is 32-bits, so a double is more precise.