Displaying decimal values with a predefined format-CodePudding

I am getting below sample values from my calculation result and I have to display is in 2 decimal points without rounding it.

-0.00123, -2.222154, -23.154, -2.13, -0.10001, -10.0012, -1.0023, 0.23, 0.56474, 1.000, 11.1111, 1.89566

I am using Decimal Format : 0.00 so,

while using "0.00" , its displaying value for -0.00128 but not displaying for -2.2386

Which should be the proper decimal format as per my need ? I have gone through the documentation here : https://developer.android.com/reference/java/text/DecimalFormat#:~:text=A DecimalFormat comprises a pattern,read from localized ResourceBundle s.

But, Still having confusion so posted question here.

CodePudding user response：

You can use BigDecimal with the desired scale (e.g. 2) and rounding mode (e.g HALF_UP) like so:

import java.math.BigDecimal
import java.math.RoundingMode

fun main() {
    val roundingMode = RoundingMode.HALF_UP
    val doubles: List<Double> = listOf(
        -0.00123, -2.222154, -23.154, -2.13, -0.10001, -10.0012,
        -1.0023, 0.23, 0.56474, 1.000, 11.1111, 1.89566
    )
    doubles.map { BigDecimal(it).setScale(2, roundingMode) }.also { println(it)  }
    // [0.00, -2.22, -23.15, -2.13, -0.10, -10.00, -1.00, 0.23, 0.56, 1.00, 11.11, 1.90]
}

Same approach in a more functional flavour (partial function instead of constants):

val fancyRound: (scale: Int, roundingMode: RoundingMode) -> (Double) -> BigDecimal =
    { scale, roundingMode ->
        { d -> BigDecimal(d).setScale(scale, roundingMode) }
    }

fun main() {
    ...
    val myRound = fancyRound(2, RoundingMode.HALF_UP)
    doubles.map { myRound(it) }.also { println(it) }

}

CodePudding user response：

You could try:

import java.math.RoundingMode;
import java.text.DecimalFormat;

class Scratch {
    public static void main(String[] args) {
        String srcNumber = "-2.2386";
        DecimalFormat formatter = new DecimalFormat("0.00");
        formatter.setRoundingMode(RoundingMode.DOWN);
        srcNumber = formatter.format(Double.valueOf(srcNumber));
        System.out.println(srcNumber);
    }
}