perl学习日记2（哈希结构）

哈希结构

%movies = ('The Shining'=> 'Kubrick', 'Ten Comandments' =>'DeMille','Goonies' =>'Spielberg');

print $movies{'The Shining'};

其中‘The Shining’是关键字，'Kubrick'是值

 

打印哈希结构中的每个关键字

foreach $film (keys %movies){

         print "$film\n";

}

输出为：

Ten Comandments

Goonies

The Shining

 

利用keys和values得到关键字和值

@directors=values %movies;

@film=keys %movies;

print "@directors\n";

print "@film\n";

输出为：

DeMille Spielberg Kubrick

Ten Comandments Goonies The Shining]

 

拷贝和组合

%New_hash=%Old_hash;

%Both=(%first,%second);  #组合后将随机排列

 

 

利用函数exists测试是否存在某个关键字

if (exists $movies{conan}){  # movies中是否存在conan这个关键字

    print "exist!"  ;

}

 

删除某个关键字 

delete $both{conan};

 

寻找数组中的唯一元素

@fishwords=qw(one fish two fish red fish blue fish);

%seen=();

foreach (@fishwords){

          $seen{$_}=1;

}

@uniquewords=keys %seen;

print "@uniquewords";

输出为：blue one red two fish

 

寻找两个数组间的不同部分和交汇部分

@stars=qw(R.Reagan C.Eastwood M.Jackson Cher S.Bono);

@pols=qw(N.Gingrich S.Thurmon R.Reagan S.Bono C.Eastwood M.Thatcher);

%seen=();

foreach (@stars){

          $seen{$_}=1;  #对电影明星的列表进行迭代操作，依次将$设置为每个名字

}

@intersection=grep($seen{$_},@pols);  #@pols中的grep函数对政治家的列表进行迭代操作，依次将$_设置给每个政治家。然后，在哈希结构%seen中寻找该名字

print "@intersection";

输出为：R.Reagan S.Bono C.Eastwood

 

需找两个数组中的不同部分

@difference=grep(! $seen{$_},@pols);

输出为：N.Gingrich S.Thurmon M.Thatcher ,即不是明星的所有政治家

 

读入txt文件，并按输入的关键字输出customer信息

#!/usr/bin/perl  -w

 

open(PH,"C:/Documents and Settings/Administrator/桌面/customers.txt") or die "Cannot open customers.txt: $!\n";

while(){    #文件句柄被读取，每一行被赋予$_

       chomp;

       ($number,$email)=(split(/\s+/,$_)) [1,2]; # $_中的这一行在空格处被分割,只取前两项

       $Phone{$number}=$_;          #将每一行存入一个哈希结构，key为number，value为一条记录

       $Email{$email}=$_;

}

close(PH);

 

print "Type 'q' to exit\n";

while (1){

       print "\nNumber?";

       $number=;chomp($number);

       $address="";

       if(!$number){

          print "E-mail?";

          $address=;chomp($address);

       }

 

       next if(!$number and !$address);

       last if($number eq 'q' or $address eq 'q');

 

       if ($number and exists $Phone{$number}) {

            print "Customer: $Phone{$number}\n";    #输出关键字为number的值

            next;

       }

 

       if ($address and exists $Email{$address}){

            print "Customer: $Email{$address}\n";

            next;

       }

       print "Customer record not found.\n";

       next;

}

print "\nAll done.\n";

 

统计单词出现的频度

open(FH,"C:/Documents and Settings/Administrator/桌面/test.txt") or die "cannot open test: $!";

while(){        #每次读取一行标准输入，为每一行设置$_

         while(/(\w[\w-]*)/g){     #以文件中的空格分隔成单词。对$_中的每个单词进行迭代操作

                 $words{$1}++;

         }

}

foreach (keys %words){

         print "$_ $words{$_}\n";     #输出每个单词的频度

}

输出为：

peach 2

banana 1

apple 2

orange 2

pear 1

 

统计单词的长度

open(FH,"C:/Documents and Settings/Administrator/×ÀÃæ/test.txt") or die "cannot open test: $!";

while(){        #每次读取一行，为每一行设置$_

         while(/(\w[\w-]*)/g){     #以文件中的空格分隔成单词。对$_中的每个单词进行迭代操作

                 $seen{length $1}++; #以单词的长度为关键字

         }

}

foreach (keys %seen){

         print "There are $seen{$_} words have $_ letter(s). \n";     #输出关键字和值

}

输出为：

There are 3 words have 6 letter(s).

There are 1 words have 4 letter(s).

There are 4 words have 5 letter(s).