Re: testing if divisible by?
On Sat, May 1, 2010 at 7:45 AM, Philip Potter philip.g.pot...@gmail.com wrote: On 1 May 2010 12:15, Paul opensou...@unixoses.com wrote: Hello all. How can I test to see if a number is divisible by say, 40? Thanks. Use the modulo operator %. Given integers $x and $y, the expression $x % $y gives the remainder when $x is divided by $y. As a result, if (and only if) $x is exactly divisible by $y, $x % $y is equal to 0. And there's the rub: number ne integer. % is fine if you're only interested in integers, but if you want to compare other numbers use fmod() from POSIX.pm: perl -MPOSIX -wle 'print POSIX::fmod(35, 17.5)' It's considerably slower than %, but it gets the job done. HTH, -- jay -- This email and attachment(s): [ ] blogable; [ x ] ask first; [ ] private and confidential daggerquill [at] gmail [dot] com http://www.tuaw.com http://www.downloadsquad.com http://www.engatiki.org values of β will give rise to dom! -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: testing if divisible by?
2010/5/3 Jay Savage daggerqu...@gmail.com: On Sat, May 1, 2010 at 7:45 AM, Philip Potter philip.g.pot...@gmail.com wrote: On 1 May 2010 12:15, Paul opensou...@unixoses.com wrote: Hello all. How can I test to see if a number is divisible by say, 40? Use the modulo operator %. Given integers $x and $y, the expression $x And there's the rub: number ne integer. % is fine if you're only interested in integers, but if you want to compare other numbers use fmod() from POSIX.pm: perl -MPOSIX -wle 'print POSIX::fmod(35, 17.5)' fmod is a fine replacement for % in general for testing remainders of floating-point valued quotients, but using it as a divisibility test requires caution and serious consideration of a different approach. It has the same issues as a floating-point equality test: that is, because floating-point is an inexact representation, the results can depend on whether a value was rounded up or down: D:\perl -MPOSIX -wle print POSIX::fmod(0.2, 0.1) 0 D:\perl -MPOSIX -wle print POSIX::fmod(0.3, 0.1) 0.1 D:\perl -MPOSIX -wle print POSIX::fmod(0.4, 0.1) 0 D:\perl -MPOSIX -wle print POSIX::fmod(0.5, 0.1) 0.1 These examples have strange results because 0.1 is not exactly representable in binary floating-point. Phil -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
testing if divisible by?
Hello all. How can I test to see if a number is divisible by say, 40? Thanks. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: testing if divisible by?
Paul wrote: Hello all. How can I test to see if a number is divisible by say, 40? Thanks. See `perldoc perlop` and search for /Multiplicative Operators/ Read the part about the % operator. -- Just my 0.0002 million dollars worth, Shawn Programming is as much about organization and communication as it is about coding. I like Perl; it's the only language where you can bless your thingy. Eliminate software piracy: use only FLOSS. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: testing if divisible by?
On 1 May 2010 12:15, Paul opensou...@unixoses.com wrote: Hello all. How can I test to see if a number is divisible by say, 40? Thanks. Use the modulo operator %. Given integers $x and $y, the expression $x % $y gives the remainder when $x is divided by $y. As a result, if (and only if) $x is exactly divisible by $y, $x % $y is equal to 0. #!perl use 5.010; # for 'say' say 5 % 2; say 6 % 2; say 7 % 2; say 79 % 40; say 80 % 40; say 81 % 40; For more information, see http://perldoc.perl.org/perlop.html#Multiplicative-Operators Phil -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: testing if divisible by?
On Sat, 2010-05-01 at 07:15 -0400, Paul wrote:
Hello all. How can I test to see if a number is divisible by say, 40?
Use the modulo operator:
my $a = 40;
my $b = 1;
if ($a % $b == 0) {
print $b is divisible by $a\n;
}
-j
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Re: testing if divisible by?
JLP == Jamie L Penman-Smithson li...@silverdream.org writes:
JLP On Sat, 2010-05-01 at 07:15 -0400, Paul wrote:
Hello all. How can I test to see if a number is divisible by say, 40?
JLP Use the modulo operator:
JLP my $a = 40;
JLP my $b = 1;
JLP if ($a % $b == 0) {
no need for the == 0 if you invert the test with unless or change the
print text.
JLP print $b is divisible by $a\n;
JLP }
uri
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