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前言

本文主要记录一下，perl中的智能匹配。

• 智能匹配符号：~~
• 智能匹配优先级，从上到下，优先级依次降低
  

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#=====================================
# 智能匹配操作符：~~
#=====================================
my $name = "I saw Fred and merry!";
#普通匹配符号
print "I found Fred in the name!\n" if $name =~ /Fred/; 
#智能匹配符号
print "I found Fred in the name!\n" if $name ~~ /Fred/; 


# 哈希数组的智能匹配
my %names = ("one" => 1, "two" => 2, "three" => 3, "four" => 4,
             "five" => 5, "six" => 6);
my $flag = 0;
foreach my $key (keys %names){
    next unless $key =~ /four/;
    $flag = $key;
    last;
}
print "I found a key matching 'four'\n" if $flag;
# 上面的语句等价于下边一条语句
print "I found a key matching 'four'\n" if %names ~~ /four/;



my @name1 = qw(one two three four five);
my @name2 = qw(one two three four five);
my $equal = 0;
foreach my $index (0..$#name1){
    last unless $name1[$index] eq $name2[$index];
    $equal ++;
}
print "The arrays have the same elemnts!\n" if $equal == @name1;
# 上面的语句等价于下边一条语句
print "The arrays have the same elemnts!\n" if @name1 ~~ @name2;



my @nums = qw(1 2 3 37 43);
my $flag = 0;
foreach my $num (@nums){
    next unless $num == 37;
    $flag = 1;
    last;
}
print "在数组中找到了 37 ！\n" if $flag;
# 上面的语句等价于下边一条语句
print "在数组中找到了 37 ！\n" if @nums ~~ /37/;
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总结