Perl语言入门-第六章-哈希-习题

1. 题目

2. 代码与输出

    ch6-family-name.pl

 1 #-----------------------------------------------------------#
 2 # Source: Learning Perl, chapter6, exercise-1
 3 # Date:   2012-01-16
 4 # Author: xiaodongrush
 5 #-----------------------------------------------------------#
 6 use 5.010;
 7 %family_name_hash = (
 8   "fred"   =>  "flintstone",
 9   "barney" =>  "rubble",
10   "wilma"  =>  "flintstone", );
11 
12 while(<>) {
13   chomp;
14   if(exists $family_name_hash{$_} ) {
15     say $_ . "'s family name is : " . $family_name_hash{$_};
16   } else {
17     say $_ . "'s family name not exist in hash";
18   }
19 }
20 #-----------------------------------------------------------#

   

ch6-wordcount.pl

 1 #-----------------------------------------------------------#
 2 # Source: Learning Perl, chapter6, exercise-2
 3 # Date:   2012-01-16
 4 # Author: xiaodongrush
 5 #-----------------------------------------------------------#
 6 use 5.010;
 7 while(<>) {
 8   chomp;
 9   if(exists $word_hash{$_}) {
10     $word_hash{$_} += 1;
11   } else {
12     $word_hash{$_} = 1;
13   }
14 }
15 foreach(sort (keys %word_hash) ) {
16   say $_ . "\t\t" . $word_hash{$_};
17 }
18 #-----------------------------------------------------------#

ch6-ENV-hash.pl

 1 #-----------------------------------------------------------#
 2 # Source: Learning Perl, chapter6, exercise-3
 3 # Date:   2012-01-16
 4 # Author: xiaodongrush
 5 #-----------------------------------------------------------#
 6 use 5.010;
 7 
 8 $max_key_len = 0;
 9 $max_value_len = 0;
10 $len_limit = 35;
11 while(($key, $value) = each %ENV) {
12   if(length($key) < $len_limit  && length($value) < $len_limit ) {
13     $max_key_len = $max_key_len > length($key) ? $max_key_len : length($key);
14     $max_value_len = $max_value_len > length($value) ? $max_value_len : length($value);
15   }
16 }
17 $format = "%-" . $max_key_len . "s  ,  %-" . $max_value_len . "s\n";
18 printf $format, "key", "value";
19 foreach(sort(keys %ENV)) {
20   if( (length($_) < $len_limit ) && (length($ENV{$_}) < $len_limit )) {
21     printf $format, $_, $ENV{$_};
22   }
23 }
24 <STDIN>;
25 #-----------------------------------------------------------#

3. 文件

    /Files/pangxiaodong/LearningPerl/ch6-answer.rar