PERL

This is intended as a personal on-line resource of perl code that I've found usefull. As time goes on, and I get more experience, I'll add more to this page. More extensive on-line crib-sheets can be found at TODO. Personally I tend to prefer to have references examples of actual code.

The keyword BLOCK refers to a generic block of perl code.

Flow control

conditional

if ( $a != $b ) { BLOCK }
   elsif($b = 3) { BLOCK }
   else { BLOCK }

unless ( $a >= $b && $a < 0) { BLOCK }

looping

LOOPLABEL: while ( $a != $b ) {
if ( $c = 0 ) { last LOOPLABEL} # exits the loop
   if ( $d = 2 ) { next LOOPLABEL} # jumps to next itteration of the loop
   $c--;
   }
for ($a=0; $a++; $a>10) {BLOCK
	}

CONDITIONAL

Numeric

• = < > <= >= != - for numeric.

String

• eq ne - for equality.
• lt le gt ge - for lexical comparison.
• cmp - returns -1 if $left lt $right, 0 if $lef eq $right, 1 of $left gt $right.
• =~ !~ - for pattern matching.

pattern matching

• . - any character
• \s - any white space character
• \S - any non-white space character
• \w - any word character (aphanumeric or underscore
• \W - any non-word character
• \d - any numeric character
• \D - any non-white space character

pattern count suffix

• ? - 0 or 1 of the previous character
• * - 0 or more of the previous character
• + - 1 or more of the previous character

concatinalting conditionals

• && - "and, if true continue to the next test"
• || - "and, if false continue to the next test"

Strings

• \n - newline
• \t - tab
• \b - backspace
• \r - carriage return
• \e - escape character
• \a - alert
• \f - from feed

operators

• . - concatinate strings
• x - duplicate "me" x 3 becomes "mememe"
• lc uc lcfirst ucfirst - case assertions
• sprintf - TODO
• index rindex - finds first/next and last occurance of string.

Lists

Hashes

GVIM maps

• :map <F2> ^y$i<<ESC>$a></<ESC>pa><ESC>bba # expands word to open and close HTML tag.
• :map <F3> :s/&/&amp;/ge<ESC>:s/</\&LT;/ge<ESC>:s/>/\&GT;/ge<ESC>
# converts & < and > to HTML equivalent.

prototypes

• map <S-F3> :s/\&LT;/</ge<ESC>:s/\&GT;/>/ge<ESC>:s/&amp;/&/ge<ESC>
  map <S-F3> :s/&LT;/</ge<ESC>:s/&GT;/>/ge<ESC>

  map  :s/</:s/>/>/ge