How to extract the first three digits after the decimal point in any calculation in Perl?

Question

For a simple division like 1/3, if I want to extract only the first three digits after the decimal point from the result of division, then how can it be done?

Answer 1

You can do it with spritnf:

my $rounded = sprintf("%.3f", 1/3);

This isn't this sprintf's purpose, but it does the job.

If you want just three digits after the dot, you can do it with math computations:

my $num = 1/3;
my $part;
$part = $1 if $num=~/^\d+\.(\d{3})/;
print "3 digits after dot: $part\n" if defined $part;

Answer 2

Using sprintf and some pattern matching. Verbose.

my $str;
my $num = 1/3;
my $res = sprintf("%.3f\n",$num);
($str = $res) =~ s/^0\.//;
print "$str\n";