perl 用grep map求交集、并集、补集

#!/usr/bin/perl

#

# 用grep map 获取两个列表的交集并集、补集

#

use strict;

my @a=("a","b","c","d","e");

my @b=("b","g","f","e");

print "列表a数据： @a \n";

print "列表b数据: @b \n";

my %a = map{$_ => 1} @a;

my %b = map{$_ => 1} @b;

my @c = map{$_ => 1} @a; # => 操作符起到了hash赋值的作用

# @a @b 交集

my @inter = grep {$a{$_}} @b; # 求交集

print "交集：@inter \n";

# @a,@b 并集

my %merge = map {$_ => 1} @a,@b; # 求并集

my @merge = keys (%merge);

print "并集：@merge \n";

# @a,@b的补集@ca，@cb，即@a和@b相对于@merge的补集

my @ca = grep {!$a{$_}} @merge;

my @cb = grep {!$b{$_}} @merge;

print "\@a的补集:@ca \n";

print "\@b的补集:@cb \n";