perl - 在 Perl 中递归打印数据结构

Question

我目前正在学习 Perl。我有 Perl 哈希，其中包含对哈希和数组的引用。散列和数组又可以包含对其他散列/数组的引用。

我编写了一个子例程来递归地解析哈希并以正确的缩进打印它们。尽管例程按预期工作，但我的导师并不相信以下代码的可读性和优雅性。

我非常感谢这里 Perl 专家对以下代码的可能优化的看法。

这是我的完整代码片段..

# Array of Arrays
$ref_to_AoA = [
     [ "fred", "barney" ],
     [ "george", "jane", "elroy" ],
     [ "homer", "marge", "bart" ],
];


#Array of Hashes
$ref_to_AoH = [ 
{
   husband  => "barney",
   wife     => "betty",
   son      => "bamm bamm",
},
{
   husband => "george",
   wife    => "jane",
   son     => "elroy",
},
];

# Hash of Hashes
$ref_to_HoH = { 
    flintstones => {
        husband   => "fred",
        pal       => "barney",
    },
    jetsons => {
       husband   => "george",
       wife      => "jane",
       "his boy" => "elroy",  # Key quotes needed.
    },
    simpsons => {
       husband   => "homer",
       wife      => "marge",
       kid       => "bart",
    },
};

# Hash which contains references to arrays and hashes
$finalHash = {
   'arrayofArrays' => $ref_to_AoA,
   'arrayofHash' => $ref_to_AoH,
   'hashofHash' => $ref_to_HoH,
};

$string = str($finalHash); 
print "$string\n";

#------------------------------------------------------------------
sub str {
    my $hash = shift;
    my ($space, $newline, $delimiter) = @_;
    $space = "" unless (defined $space);
    $newline = "\n\n\n" unless (defined $newline);
    $delimiter = "\n--------------------------------------------" unless (defined $delimiter);
    my $str = "";

    for (sort keys %{$hash}) {
        my $value = $hash->{$_};
        $str .= "$newline$space$_ == $value$delimiter";
        $str .= recurseErrors($value,$space);
    }
    $str;
}

#------------------------------------------------------------------
sub recurseErrors {
    my $str;
    my ($value,$space) = @_;
    my $ref = ref $value;

    if ($ref eq 'ARRAY') {
        my $i = 0;
        my $isEmpty = 1;
        my @array = @$value;
        $space .= "\t";
        for my $a (@array) {
            if (defined $a) {
                $isEmpty = 0;
                $str .= "\n$space$_\[$i\] :";
                $str .= recurseErrors($a,$space);
            }
            $i++;
        }
        $str .= "= { }" if ($isEmpty);

    } elsif ($ref eq 'HASH') {
        $space .= "\t";
        for my $k (sort keys %$value) {
            if ( ( ref($value->{$k}) eq 'HASH') || (ref $value->{$k} eq 'ARRAY') ) {
                my $val = $value->{$k};
                $str .= "\n\n$space$k == ";
                $str .= "$val";
            }
            else {
                $str .= "\n$space$k == ";
            }
            $str .= recurseErrors($value->{$k},$space);
      }

      # we have reached a scalar (leaf)
    } elsif ($ref eq '') {
        $str .= "$value";
    }
$str
}
#------------------------------------------------------------------

输出:

arrayofArrays == ARRAY(0x9d9baf8)--------------------------------------------    arrayofArrays[0] :        arrayofArrays[0] :fred        arrayofArrays[1] :barney    arrayofArrays[1] :        arrayofArrays[0] :george        arrayofArrays[1] :jane        arrayofArrays[2] :elroy    arrayofArrays[2] :        arrayofArrays[0] :homer        arrayofArrays[1] :marge        arrayofArrays[2] :bartarrayofHash == ARRAY(0x9d9bba8)--------------------------------------------    arrayofHash[0] :        husband == barney        son == bamm bamm        wife == betty    arrayofHash[1] :        husband == george        son == elroy        wife == janehashofHash == HASH(0x9da45f8)--------------------------------------------    flintstones == HASH(0x9d9bb48)        husband == fred        pal == barney    jetsons == HASH(0x9d9bbf8)        his boy == elroy        husband == george        wife == jane    simpsons == HASH(0x9d9bc48)        husband == homer        kid == bart        wife == marge

Answer 1

1. 始终使用使用严格；
2. 要成为一个好 child ，也要使用使用警告。
3. 子例程使用的名称应该清楚地表明子例程的作用。 “recurseErrors”有点违反了这一原则。是的，它确实会递归。但什么错误呢？
4. 在每个子例程的第一行，您应该声明并初始化所有参数。 recurseErrors 首先声明 $str，然后声明其参数。
5. 不要像在 str() 中那样混合使用 shift 和 = @_
6. 您可能会考虑将现在称为 recurseErrors 的内容分解为处理数组和哈希的专用例程。
7. 无需像第 99 行和第 109 行那样引用变量。

除此之外，我认为你的教练那天过得很糟糕。