How can I use String.format(format, args) to format a double like below?
2354548.235 -> 2,354,548.23
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7 Answers
String.format("%1$,.2f", myDouble);
String.format automatically uses the default locale.
5 Comments
Olivier Grégoire
You can also use a specific locale by using
String.format(Locale.GERMAN, "%1$,.2f", myDouble);
Moesio
If there is more than one double to format, use %1, %2, and so on. For example String.format("%1$,.2f, %2$,.2f", myDouble, aDouble)
Matt Passell
I believe the "%1$" is optional in this case. Works for me with just "%,.2f" as the format String.
praneetloke
Yes, Matt is right.
%1, %2 and so on can be used to re-order the output based on the index of your input arguments. See this. You can omit the index and the default order will be assumed by the formatter.
Mitulát báti
You should give an explanation what the different parts mean.
String.format("%4.3f" , x) ;
It means that we need total 4 digits in ans , of which 3 should be after decimal . And f is the format specifier of double . x means the variable for which we want to find it . Worked for me . . .
5 Comments
Michael Fulton
I think it means it will be the fourth variable in the arguments which follow and have 3 places after the decimal.
parsecer
@MichaelFulton It's not that easy:
String.format("%014.3f" , 58.656565) -> 0000000058,657: 14 symbols in total: 8 zeroes and 5 numbers and 1 comma. So in this case number 14 means the total number of symbols (extra ones get replaced with leading zero, could go without, then it would replace with space) in the result string. The .3 part is completely independent here.parsecer
However here:
String.format("%014.3f" , 58.656565) -> 58,657. I take it because the preference goes to the .3f part: it first prints the number with 3 decimal places and after if there are symbols left it prints leading spaces (or zeroes/whatever). In this case the number is 2 + 3 + 1 = 6 symbols and we only wanted to print 4, so there are certainly no extra spaces.
RAM237
@parsecer you posted the same
String.format("%014.3f" , 58.656565) two times, but the result is different, am I missing something?parsecer
@RAM237 Yeah there must have been the typo. But now I don't remember what it was about
If you want to format it with manually set symbols, use this:
DecimalFormatSymbols decimalFormatSymbols = new DecimalFormatSymbols();
decimalFormatSymbols.setDecimalSeparator('.');
decimalFormatSymbols.setGroupingSeparator(',');
DecimalFormat decimalFormat = new DecimalFormat("#,##0.00", decimalFormatSymbols);
System.out.println(decimalFormat.format(1237516.2548)); //1,237,516.25
Locale-based formatting is preferred, though.
1 Comment
Honza Zidek
Useful answer! However, the last sentence "Locale-based formatting is preferred, though" does not make sense without context. There are pretty good use cases where you should NOT use locale-based formatting, when you want to generate a specific format of the String. E.g. you are implementing export of your data to an external file and you want to have full control over the format, not dependent on the current (or any) locale.
code extracted from this link ;
Double amount = new Double(345987.246);
NumberFormat numberFormatter;
String amountOut;
numberFormatter = NumberFormat.getNumberInstance(currentLocale);
amountOut = numberFormatter.format(amount);
System.out.println(amountOut + " " +
currentLocale.toString());
The output from this example shows how the format of the same number varies with Locale:
345 987,246 fr_FR
345.987,246 de_DE
345,987.246 en_US
Comments
public class MainClass {
public static void main(String args[]) {
System.out.printf("%d %(d %+d %05d\n", 3, -3, 3, 3);
System.out.printf("Default floating-point format: %f\n", 1234567.123);
System.out.printf("Floating-point with commas: %,f\n", 1234567.123);
System.out.printf("Negative floating-point default: %,f\n", -1234567.123);
System.out.printf("Negative floating-point option: %,(f\n", -1234567.123);
System.out.printf("Line-up positive and negative values:\n");
System.out.printf("% ,.2f\n% ,.2f\n", 1234567.123, -1234567.123);
}
}
And print out:
3 (3) +3 00003
Default floating-point format: 1234567,123000
Floating-point with commas: 1.234.567,123000
Negative floating-point default: -1.234.567,123000
Negative floating-point option: (1.234.567,123000)Line-up positive and negative values:
1.234.567,12
-1.234.567,12
Comments
There are many way you can do this. Those are given bellow:
Suppose your original number is given bellow: double number = 2354548.235;
Using NumberFormat and Rounding mode
NumberFormat nf = DecimalFormat.getInstance(Locale.ENGLISH);
DecimalFormat decimalFormatter = (DecimalFormat) nf;
decimalFormatter.applyPattern("#,###,###.##");
decimalFormatter.setRoundingMode(RoundingMode.CEILING);
String fString = decimalFormatter.format(number);
System.out.println(fString);
Using String formatter
System.out.println(String.format("%1$,.2f", number));
In all cases the output will be: 2354548.24
Note:
During rounding you can add RoundingMode in your formatter. Here are some Rounding mode given bellow:
decimalFormat.setRoundingMode(RoundingMode.CEILING);
decimalFormat.setRoundingMode(RoundingMode.FLOOR);
decimalFormat.setRoundingMode(RoundingMode.HALF_DOWN);
decimalFormat.setRoundingMode(RoundingMode.HALF_UP);
decimalFormat.setRoundingMode(RoundingMode.UP);
Here are the imports:
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;
Comments
Use DecimalFormat
NumberFormat nf = DecimalFormat.getInstance(Locale.ENGLISH);
DecimalFormat decimalFormatter = (DecimalFormat) nf;
decimalFormatter.applyPattern("#,###,###.##");
String fString = decimalFormatter.format(myDouble);
System.out.println(fString);
Comments
