java cut string after 2 decimal digits?

Question

I have this string

17.12121

and I want to save it only as

17.12

I have try to use this command :

answer = String.format("%.2f", str1);

but he give an exception

java.util.IllegalFormatConversionException: f != java.lang.String

why ?

in the end I wnat the answer to be x.xx

Thanks ,

`%f` is used to format floating point numbers, not Strings. – Kayaman Jul 12 '18 at 11:05 — Kayaman, Jul 12 '18 at 11:05
`answer = String.format("%.2f", Float.valueOf(str1));` – Shark Jul 12 '18 at 11:10 — Shark, Jul 12 '18 at 11:10

score 1 · Answer 1 · answered Jul 12 '18 at 11:06

To use %f you should to have a float not a String, instead you can use :

answer = String.format("%.2f", Float.valueOf(str1));
                               ^^^^^^^^^^^^^^^^^^^

Note that the format follow the Locale, so the dot can be converted to , the result can be 17,12 instead of 17.12 to make sure you get dot you can use Locale.US like this :

answer = String.format(Locale.US, "%.2f", Float.valueOf(str1));

score 1 · Accepted Answer · answered Jul 12 '18 at 11:07

If you want to use float formatting, you could parse your string as a float, and then use "%.2f.

If you just want to cut your string two places after the decimal point, you could just find the . character and take a substring based on its position.

int index = str1.indexOf('.');
if (index >= 0) {
    answer = str1.substring(0, index+3);
} else {
    answer = str1;
}

score 0 · Answer 3 · edited Jul 12 '18 at 13:21

0

BigDecimal d= new BigDecimal("17.12121").setScale(2, RoundingMode.DOWN);
System.out.println(d);

edited Jul 12 '18 at 13:21

Tobias Reich

4,952
3
47
90

answered Jul 12 '18 at 11:12

Debapriya Biswas

1,079
11
23

java cut string after 2 decimal digits?

3 Answers3