#11 The Game Of Life
use PDL; use PDL::Image2D;
use PDL::Graphics::TriD;nokeeptwiddling3d;
$d=byte(random(zeroes(40,40))>0.85);
$k=byte [[1,1,1],[1,0,1],[1,1,1]];
do{ imagrgb [$d]; $s=conv2d($d,$k);
$d&=($s>4);$d&=($s>1);$d|=($s==3);}
while (!twiddle3d);
Courtesy of Robin Williams
appeared in Issue 10
#12 DeMorgan's Rule
if (!$a || $b != $c) { ... }
is equivalent to
unless ( $a && $b == $c ) { ... }
appeared in Issue 10
#13
Little-known facts about qr// (new with Perl 5.005): it has a magic print value, and it's an object of type Regexp.
% perl -le 'print "My regex: ", qr/^watch/i'
My regex: (?i-xsm:^watch this)
$rob = qr/red/i;
if ($rob->match("Fred Flintstone")) {
print "Got obj fred!\n";
}
sub Regexp::match {
my $self = shift;
my $arg = @_ ? shift : $_;
return $arg =~ /$arg/;
}
Courtesy of Tom Christiansen
appeared in Issue 11
#14
Transpose a two-dimensional array:
@matrix_t = map{my$x=$_;[map {$matrix[$_][$x]}
0..$#matrix]}0..$#{$matrix[0]};
Courtesy of Tuomas J. Lukka
appeared in Issue 11
#15 Primality
use PDL; use PDL::Graphics::TriD; $s=40;$a=zeroes
2*$s,$s/2;$t=$a->xlinvals(0,6.284);$u=$a->ylinvals
(0,6.284);$o=5;$i=1;$v=$o-$o/2*sin(3*$t)+$i*sin$u;
imag3d([$v*sin$t,$v*cos$t,$i*cos($u)+$o*sin(3*$t)]);
Courtesy of Tuomas J. Lukka
appeared in Issue 11
#16
This code converts any GIF to an HTML table--each cell of the table corresponds to a pixel of the image. Use this to make your web advertisements seem like important content and circumvent Lincoln's Apache::AdBlocker. :
This code is online at http://tpj.com/one-liners.
use GD;$f='#ffffff';$T=table;sub p{print @_}
p"<body bgcolor=$f>";for(@ARGV){open*G,$_ or(warn("$_:
$!")&&next);$g=GD::Image->newFromGif(G)||(warn$_,
": GD error"and next);@c=map{$_!=$g->transparent
?sprintf'#'.('%.2x'x3),$g->rgb($_):$f}0..
$g->colorsTotal;p"<$T border=0 cellpadding=0
cellspacing=0>";($x,$y)=$g->getBounds;for$j(0..$y)
{p"<tr>";for($i=0;$i<$x;$i++){$s=1;$s++&&$i++while($i+1
<$x&&$g->getPixel($i+1,$j)==$g->getPixel($i,$j));p"
<td bgcolor=",$c[$g->getPixel($i,$j)],"
colspan=$s> "}}p"</$T>"}
Courtesy of Mike Fletcher
appeared in Issue 11
#17
Ever wish backquotes didn't interpolate variables? qx() is a synonym for backquotes, but if you use single quotes as a delimiter, it won't interpolate: qx'echo $HOME' works.
Courtesy of Tom Christiansen
appeared in Issue 11
#18
"Use m//g when you know what you want to keep, and split() when you know what you want to throw away."
Courtesy of Randal L. Schwartz
appeared in Issue 11
#19
Count the lines of pod and code in a Perl program:
@a=(0,0);while(<>){++$a[not m/
^=\w+/s .. m/^=cut/s]} printf"%d
pod lines, %d code lines\n",@a;
Courtesy Sean M. Burke
appeared in Issue 11
#20 Results of the SunWorld reader survey (4,106 respondents)
Which of the following open source products do you have installed for WORK use?
Perl 83%
Sendmail 74%
Apache 72%
Linux 64%
Tcl 52%
Python 24%
Which of the following open source products do you have installed for PERSONAL use?
Perl 79%
Linux 77%
Apache 63%
Sendmail 61%
Tcl 55%
Python 34%
appeared in Issue 11
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