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PERL

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					Quick Overview
   scalar names begin with $
   array names begin with @
   hash names begin with %

   my indicates private (local) variable
   if not declared with my, then variable is
    global (package)
@weekend = (“Saturday“, “Sunday”);
print “@weekend”;
print “I love “.$weekend[0].”\n”;
   http://www.cs.mcgill.ca/~abatko/computers/programming/perl/howto/hash /

my %hash = (); #clear hash
# add entries using literals & variables
$hash{ 'CSCI306' } = 'Java';
$l = 'C++';
$c = 'CSCI261';
$hash{$c} = $l;
# print size and all entries
print "size of hash: " . keys( %hash ) . ".\n";
for my $key ( keys %hash ) {
        my $value = $hash{$key};
        print "$key => $value\n";
    }
# search for entry
if ($hash{$c} ne "") {
  print $hash{$c}."\n";
}
$filename = "data.txt";
# open file, DATA is file handle
open(DATA,$filename);
# read file into array
@data = <DATA>;
# process each line read from file
foreach $line (@data)
{
   # split places elements into array, based on
   # delimiter. Many other options, do a Google
   @words = split(/ /,$line);
   foreach $word (@words)
   {
     print($word."\n");
   }
}
# good to declare subs at top of program, not
  required
sub trim;
…
$trimmedString = &trim($myString);
..
sub trim($)
{
  # can get parameters using shift
  my $string = shift;
  # regex to remove whitespace \s
  #^ is beginning, $ is end
  $string =~ s/^\s+//;
  $string =~ s/\s+$//;

    return $string;
}
   match text
    $string =~ /target/;
   match beginning
    $string =~ /^target/;
   match end
    $string =~ /target$/;
   match ignore case
    $string =~ /target/i;
   remove punctuation
    $string =~ s/\W/ /g;
simple replacement
$string =~ /target/replacement/;

				
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posted:11/25/2011
language:English
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