Print 1 digit after decimal point in Java

Question

I’m trying to print a number with digits after the decimal point, but i want to show just one digit.

ratio = (double) comparisons / arrayLength;

(while ratio is double and comparisons , arrayLength is int).

i'm doing the calculation in one class and add the result to a string (when later is returned from a method), and doing the printing in a test class.

i need to change ratio and not allowed to use printf in the test class.

thanks for your help

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ChasedByDeath · Accepted Answer · 2020-04-11T19:20:18.227

1

Since you're already keeping the result in a string, you can do this-

 String result = String.format("%.1f",ratio);

If you want to add the answer to an existing string then you can do this-

result = String.format(result+"%.1f",ratio);

An example would be like this-

 String s = String.format("%.1f",2.3535);

Output- 2.4

edited Apr 11 '20 at 19:20

answered Apr 11 '20 at 18:55

ChasedByDeath

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i did that, but now it's print only ratio and not the rest of the string – aye Apr 11 '20 at 19:05
Do you want to add the "ratio" to an existing string? Like "The ratio is - 2.4"? – ChasedByDeath Apr 11 '20 at 19:07
yes, it's an existing string – aye Apr 11 '20 at 19:09
Then do this- **result = String.format(result+"%.1f",ratio);** It will concatenate the ratio with the string. – ChasedByDeath Apr 11 '20 at 19:11
it worked! thank you very mach – aye Apr 11 '20 at 19:15

score 0 · Answer 2 · answered Apr 11 '20 at 18:55

0

You could explicitly format the number with a DecimalFormat:

DecimalFormat df = new DecimalFormat("###.#");
String formatted = df.format(ratio);
System.out.printly("ratio is " + ratio);

answered Apr 11 '20 at 18:55

Mureinik

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Print 1 digit after decimal point in Java

2 Answers2