学习perl哈希数据结构的代码

#!/usr/bin/perl -w 
##Code Begin############## 
use strict; 
 
print "方法一：中间数组+keys和values函数法n"; 
my %hash = ("a"=>1000,"b"=>2000,"c"=>3000); 
if (%hash) { 
my @k = keys %hash; 
my @v = values %hash; 
my $count = keys %hash; #得到 3，是指有3 个 key/value 对 
print "@k","n"; 
print "@v","n"; 
print "$countn"; 
} else { 
print "The %hash is not defined any elment already! n"; 
}; 
 
print "方法二:while+each函数法n";  
while ((my $key, my $value) = each %hash){ 
print "$key => $valuen"; 
} 
 
print "方法三：foreach+keys函数法n"; 
foreach (sort keys %hash) {  
print "$_ => $hash{$_}n"; 
# 也可以使用额外的临时变量$key 
# foreach $key (sort keys %hash) { 
# print “ $key => $hash{key}n” ; 
}; 
##Code End################ 
print `sed -n '$!p' $0 |cat -n`;