Perl 遍历散列

落日映苍穹つ 2022-08-13 09:59 143阅读 0赞

我们在遍历二维或多维的散列时, 可以采用递归的方法.

1. 首先查看每个value的值类型, 如HASH, ARRAY, 还是简单的标量

2. 如果value的值类型是HASH,则递归直到找到相应的ARRAY 或者标量

3. 如果value的值类型是ARRAY,则通过循环打印出各个元素

4. 如果value的值类型是标量,则直接打印

my %kids\_of\_wife;  
$kids\_of\_wife\{"Jacob"\}\{"John"\} = \{"Leah" => \["Reuben", "Simeon", "Levi", "Judah", "Issachar", "Zebulun"\],  
                           "Rachel" => \["Joseph", "Benjamin"\],  
                           "Bilhah" => \["Dan", "Naphtali"\],  
                            "Zilpah" => \["Gad", "Asher"\],\};  
my @array = (1,2,3,4,5);  
@\{$kids\_of\_wife\{"Jacob"\}\{"John"\}\{"Betty"\}\} = @array;

$kids\_of\_wife\{"Jacob1"\}\{"John1"\} = \{"Leah1" => \["Reuben1", "Simeon1", "Levi1", "Judah1", "Issachar1", "Zebulun1"\],  
                           "Rachel1" => \["Joseph1", "Benjamin1"\],  
                           "Bilhah1" => \["Dan1", "Naphtali1"\],  
                           "Zilpah1" => \["Gad1", "Asher1"\],\};

my %a;  
$a\{m\}\{n\}=1;  
$a\{m\}\{n2\}=5;  
$a\{m\}\{n3\}=2;  
$a\{m1\}\{n\}=1;

$a\{m1\}\{q\}=8;  
PrintHash(/%a, "");  
PrintHash(/%kids\_of\_wife, $keyWord);

sub PrintHash  
\{  
    my ($hash, $keyWord) = @\_;  
    if ($hash =~ /^HASH/)  
    \{  
         while(my ($key,$value)=each(%$hash))  
        \{  
            if ($value =~ /^HASH/)  
            \{  
                $keyWord = $keyWord."$key/:/:";  
                PrintHash($value,$keyWord  );  
                $keyWord = "";  
            \}  
            elsif ($value =~ /^ARRAY/)  
            \{  
                my @array = @\{$value\};  
                print "$keyWord$key => ";  
                foreach (@array)  
                \{  
                    print "$\_  ";  
                \}  
            \}  
            else  
            \{  
                print "$keyWord$key => $value/n";  
            \}  
            print "/n";  
        \}  
    \}  
\}

Result:

m1::n => 1  
m1::q => 8  
m::n => 1  
m::n2 => 5  
m::n3 => 2  
Jacob1::John1::Rachel1 => Joseph1  Benjamin1  
Jacob1::John1::Leah1 => Reuben1  Simeon1  Levi1  Judah1  Issachar1  Zebulun1  
Jacob1::John1::Zilpah1 => Gad1  Asher1  
Jacob1::John1::Bilhah1 => Dan1  Naphtali1  
Jacob::John::Zilpah => Gad  Asher  
Jacob::John::Bilhah => Dan  Naphtali  
Jacob::John::Leah => Reuben  Simeon  Levi  Judah  Issachar  Zebulun  
Jacob::John::Betty => 1  2  3  4  5  
Jacob::John::Rachel => Joseph  Benjamin