how to always round up in perl?

cburger has asked for the wisdom of the Perl Monks concerning the following question:

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Re: how to always round up in perl? by toolic (Bishop) on Feb 25, 2011 at 02:03 UTC
This is a perlfaq: `perldoc -q round` [download] POSIX::ceil: `use warnings; use strict; use POSIX; for (3.3, 3.6, 3003.3) { print $_, "\t", ceil($_), "\n"; } __END__ 3.3 4 3.6 4 3003.3 3004` [download]	[reply] [d/l] [select]
Re: how to always round up in perl? by umasuresh (Hermit) on Feb 25, 2011 at 01:59 UTC
Try POSIX!	[reply]
Re: how to always round up in perl? by philipbailey (Curate) on Feb 25, 2011 at 09:10 UTC
Or if you do not want to import a mass of functions into your namespace from the POSIX module, just do this: `my $n = 3.3; my $ceiling = int($n + 1);` [download] (Update) Above is incorrect, as pointed out by others. This works: `my $ceiling = ($n == int $n) ? $n : int($n + 1);`	[reply] [d/l] [select]
Re^2: how to always round up in perl? by chrestomanci (Priest) on Feb 25, 2011 at 09:19 UTC
That fails if $n is allready an integer. You would need something like: `my $n = 3.0; my $ceiling = int($n); $ceiling += 1 if $ceiling != $n;` [download] Or as a one liner: `my $ceiling = int($n) + ($n != int($n));` [download]	[reply] [d/l] [select]
Re^3: how to always round up in perl? by sbohning (Initiate) on Oct 11, 2021 at 17:01 UTC
They also fail with negative non-integers. `perl -MPOSIX=ceil -e "$n=-2.1; print($n, ' POSIX: ', ceil($n))" # -2.1 POSIX: -2 perl -e "$n=-2.1; print($n, ' other: ', int($n) + ($n != int($n)))" # -2.1 other: -1` [download]	[reply] [d/l]
Re^2: how to always round up in perl? by Ratazong (Monsignor) on Feb 25, 2011 at 09:18 UTC
Which I wouldn't recommend, because it fails in the following situation (with $n2) ... `my $n1 = 3.3; my $n2 = 4; print int($n1 + 1)," ",int($n2 + 1), "\n";` [download]	[reply] [d/l]
Re^2: how to always round up in perl? (selective import) by toolic (Bishop) on Feb 25, 2011 at 14:25 UTC
if you do not want to import a mass of functions into your namespace from the POSIX module ... just do this: `use warnings; use strict; use POSIX qw(ceil); for (3.3, 3.6, 3003.3) { print $_, "\t", ceil($_), "\n"; } __END__ 3.3 4 3.6 4 3003.3 3004` [download] According to How to Import, this selectively imports only the `ceil` function. Alternately, you could import nothing and call the function using `POSIX::ceil`.	[reply] [d/l] [select]