perl学习之哈希

#!/usr/bin/perl

use warnings;
#use strict强制所有变量必须用my来声明，
#当试图使用不是用my声明的裸单词(变量或函数名)时，编译无法通过
use strict;

#创建简单的hash表
my %student = (
   "name" => "HuiDong",
   "id"   => 1021400001,
   "age"  => 25,
);

#对hash表进行操作

#返回hash表中的所有keys
print my @key    = keys%student;
#返回hash表中的所有values
print my @values = values%student;

#迭代hash的每一个元素
while ((my $key, my $value) = each %student) {
  print "$key=>$value\n";  
}

#查看hash表中是否存在某个key
if (exists$student{'name'}) {
  print "exist\n";  
}

#根据变量自动创建hash
my $string = "name HuiDong";
my ($name_t, $name) = split(/\s/, $string);

my %dich = ();
$dich{$name_t} = $name;

while ((my $key, my $value) = each%dich) {
  print "$key=>$value\n";  
}

#创建多层hash表并实现访问
my %students;
%students = (
  "student1" => {"name" => "name1",
                 "id"   => 10214,
                 "mark" => 100,
                 },
  "student2" => {"name" => "name2",
                 "id"   => 10215,
                 "mark" => 50,
                 },
);
#访问方式一
print $students{"student1"}{"name"}."\n";
#访问方式二
my $studentreport = $students{"student2"};
print ${$studentreport}{"name"}."\n";

#hash表中内嵌数组
my %game = (
  "武器店" => [123,35],
  "魔法店" => [85, 196],
);

print $game{"武器店"}->[0]."\t";
print $game{"武器店"}->[1]."\n";

#清空和删除hash表
undef %student;#清空整个hash表

foreach my $key(keys %student) {
  delete $student{$key}; #删除hash 
}