<![CDATA[
#!perl -w
use strict;
# test ideas in chapter 1
my @numbers = (10,20,30,40,50);
my @some = @numbers[1..3,0,4];
print join(" ",@some), "\n";
while ( my $filename = shift @ARGV ) {
if ( open( FILE, "< $filename" ) ) {
while ( my $line = <FILE> ) {
print $line;
}
close FILE;
} else {
warn("Unable to open file $filename: $!\n");
}
}
my %AminoAcids = ( Cys => "Cysteine", Asp => "Aspartic Acid", Glu => "Glutamic Acid");
my @AA = values %AminoAcids;
print "Values: ", join(", ", @AA), "\n";
# print in Amino Acids in lexical (alphabetical order)
my @lexical_order = sort keys %AminoAcids;
while ( my $key = shift @lexical_order ) {
print "$key = $AminoAcids{$key}\n";
}
# print in Amino Acids in value order
my @value_order = sort { $AminoAcids{$a} cmp $AminoAcids{$b} } keys %AminoAcids;
while ( my $key = shift @value_order ) {
print "$key = $AminoAcids{$key}\n";
}
my %check = ( Undefined => undef,
Zero => 0,
Empty => "",
One => 1,
String => "anything"
);
foreach my $key (sort keys %check) {
no warnings;
print "Key check: $key\tvalue:->$check{$key}<-\n";
if ( exists $check{$key} ) {
print "\tExists, ";
} else {
print "\tDoes not exist, ";
}
if ( defined $check{$key} ) {
print "Defined, ";
} else {
print "Is not defined, ";
}
if ( $check{$key} ) {
print "True\n";
} else {
print "Is not true\n";
}
}
print "Home directory: ", $ENV{'HOMEPATH'}, "\n";
]]>