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The Perl Journal One-Liners

TPJ One-Liner #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

TPJ One-Liner #14

Transpose a two-dimensional array: 

@matrix_t = map{my$x=$_;[map {$matrix[$_][$x]}
                     0..$#matrix]}0..$#{$matrix[0]};

Courtesy of Tuomas J. Lukka

TPJ One-Liner #15

TPJ One-Liner #15

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

TPJ One-Liner #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/tpj/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=$s>&nbsp"}}p"</$T>"}

Courtesy of Mike Fletcher

TPJ One-Liner #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

TPJ One-Liner #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

TPJ One-Liner #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

TPJ One-Liner #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%

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