A lot of times, golf is about shaving off a few characters here and there. I'm sure these have been pointed out before, but:
- y///c is one character shorter than length
- ($x=~/./g) is two characters shorter than (split//,$x)
- bareword=> can save a character over 'bareword',
For control flow, you want
for,
map, and punctuation.
map and
for are largely interchangeable.
while is almost never necessary. Don't forget about the C-language-style
for(;;), although it's rarely a gain. Postfix your operators; statement-modifier
for doesn't require the parens or the braces that make a
BLOCK. Replace branching
if() statements with ternary or logical operators. Precedence rules will help here; also, remember that in Perl, true is '1' and false is the empty string. If you don't need the short-circuiting, you can use the bitwise flavor of
& and
|. Know which builtin variables are used and what special effects they have. (
$- and
$=, I'm looking at you.)
From the snippets you have posted:
$o .= $p >= 0 ? $a[$p] : $_;
could become
$o .= $p < 0 ? $_ : $a[$p] and
$r =~ s/[^a-z]//g;
could become
$r =~ y/a-z//cd;