CODEWITHSUNDEEP
javafloating-point-precision
Abhay
Abhay

Reputation: 697

Formatting Floating point number in java upto 3 precison of decimal

I have a variable type float.I wanted to print it upto 3 precision of decimal including trailing zeros.

Example :

2.5 >> 2.500

1.2 >> 1.200

1.3782 >> 1.378

2 >> 2.000

I am trying it by using

DecimalFormat _numberFormat= new DecimalFormat("#0.000");
Float.parseFloat(_numberFormat.format(2.5))

But it is not converting 2.5 >> 2.500.

Am I doing something wrong..

Please help..

Upvotes: 5

Views: 12821

Answers (4)

Tarsem Singh
Tarsem Singh

Reputation: 14199

Here is mistake Float.parseFloat this is converting back to 2.5

Output of _numberFormat.format(2.5) is 2.500

But this Float.parseFloat makes it back to 2.5

So your code must be

DecimalFormat _numberFormat= new DecimalFormat("#0.000");
_numberFormat.format(2.5)

Upvotes: 7

Debojit Saikia
Debojit Saikia

Reputation: 10632

Try formatting as below : 

DecimalFormat df = new DecimalFormat();
df.applyPattern(".000");
System.out.println(df.format(f));

Upvotes: 3

Vince
Vince

Reputation: 1527

Try

System.out.printf("%.3f", 2.5);

The printf-Method allows you to specify a format for your input. In this case %.3f means

Print the following number as a floating point number with 3 decimals

Upvotes: 2

nanofarad
nanofarad

Reputation: 41271

You're writing a decimal to a formatted string then parsing it into a float.

Floats don't care if they read 2.500 or 2.5, although the former is formatted.

The float is not going to hold trailing zeroes as IEEE754 cannot handle specifying the number of significant fihgures.

Upvotes: 1

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