On Jul 12, Jorge Almeida said:
Is there some way to really round a number to a given number of digits
after the point?
sprintf doesn't seem to work:
$ perl -e '$a=11.45; $a=sprintf("%.1f", $a); print $a;'
11.4
From what you learned in math class, sprintf() does it wrong in some
cases. But Perl's sprintf() just does what C's sprintf() does:
1.5 -> 2
2.5 -> 2
3.5 -> 4
4.5 -> 4
It's weird. Suffice to say, here's a rounding function that behaves like
you learned about in math class:
sub round {
my ($n, $places) = @_;
my $factor = 10 ** ($places || 0);
return int(($n * $factor) + ($n < 0 ? -1 : 1) * 0.5) / $factor;
}
The first argument is the number to round, and the second argument is the
number of places after the decimal point to round to.
round(123.456,-2) --> 100
round(123.456,-1) --> 120
round(123.456) --> 123
round(123.456,0) --> 123
round(123.456,1) --> 123.5
round(123.456,2) --> 123.46
It works with positive and negative numbers (both as the numbers BEING
rounded and the places to round TO).
--
Jeff "japhy" Pinyan % How can we ever be the sold short or
RPI Acacia Brother #734 % the cheated, we who for every service
http://japhy.perlmonk.org/ % have long ago been overpaid?
http://www.perlmonks.org/ % -- Meister Eckhart
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
<http://learn.perl.org/> <http://learn.perl.org/first-response>
