perl常量+多维数组+变量的初始化的例子

#!/bin/perl

use strict;
use warnings;

my $test = "asdf";
print "${test}_test2n";

#constant
use constant {
    AAA => "aaa",
    BBB=> "bbb",
    MIN_TOTAL => 12,
    SCORE_PASS => 90,
    SCORE_RED => 70,
};

print AAA;
print SCORE_PASS;

#two dimesion arrays
my @steps = (
      ["aaa", "aaavalue"],
      ["bbb","bbbvalue"],
      ["ccc","cccvalue"]
);
print "n";
foreach my $i (0 .. $#steps){
  print "$steps[$i][0]:$steps[$i][1]n";
}

#!/bin/perl
my $a1;
print "$a1n";
my $a2 = undef;
print "$a2n";
if(!defined($a1)){print "a1 is not definedn";}
if(!$a2){print "a2 is not definedn";}
my $a3='';
if(!$a3){print "a3 is empty stringn";}