Question

我将尝试用一个例子来说明这一点。举一个Hash of Hashes的常见例子：

my %HoH = (
    flintstones => {
        lead => "fred",
        pal  => "barney",
    },
    jetsons => {
        lead      => "george",
        wife      => "jane",
        "his boy" => "elroy",
    },
    simpsons => {
        lead => "homer",
        wife => "marge",
        kid  => "bart",
    },
);

出于我的目的，我希望能够为％HOH添加一个未命名的或匿名的哈希值。在运行时，我不需要（或能够）定义这些子哈希值。我怎样才能用Perl实现这个目标？

我读过的所有内容（我已经阅读过Perldocs和Google已经阅读过）似乎都展示了所有子黑客（例如“flintstones”，“jetsons”和“simpsons”）的定义。

我正在做的是尝试构建一个父Hash，它将包含带有CSV文件行的子哈希：

%TopHash = (
   %Line1 => {
      cell01 => $some_value1a;
      cell02 => $some_value2a;
      cell03 => $some_value3a;
   },
   %Line2 => {
      cell01 => $some_value1b;
      cell02 => $some_value2b;
      cell03 => $some_value3b;
   },
   %Line3 => {
      cell01 => $some_value1c;
      cell02 => $some_value2c;
      cell03 => $some_value3c;
   },
# etc
# etc
# etc

    );

我需要的“％LineX”哈希值在运行时才知道（因为它们代表了在运行时读取的CSV行数）。

有什么想法吗？如果还不清楚......我仍然试图绕着Perl哈希。

Answer 1

要在运行时添加匿名哈希，请将其分配为普通哈希元素：

$HoH{key} = { foo => 42 };

或

$HoH{key} = $hash_ref;

或

$HoH{key} = \%hash;

Answer 2

首先从正在解析的当前行创建哈希

my %lineHash = (
    cell01 => $some_value1a,
    cell02 => $some_value1b,
    cell03 => $some_value1c
);

或直接创建对哈希的引用

my $lineHashRef = {
    cell01 => $some_value2a,
    cell02 => $some_value2b,
    cell03 => $some_value2c
};

然后将它添加到整个哈希中，记住嵌套的perl结构只包含对其他结构的引用。

$topHash{line1} = \%lineHash;
$topHash{line2} = $lineHashRef;

更新的示例给出了一个解析数据数组的循环

my %topHash;
foreach my $i (0 .. $#data) {
    my %tempHash;
    // stuff here to parse $data[$i] and populate %tempHash
    $topHash{"line$i"} = \%tempHash;
}

Answer 3

#!/usr/bin/perl

use strict;

my %HoH = (
    line01 => {
        cell01 => "cell0101",
        cell02 => "cell0102",
        cell03 => "cell0103"
    }
);

$HoH{"line02"}    =
    {
        cell01 => "cell0201",
        cell02 => "cell0202",
        cell03 => "cell0203"
    };

foreach my $hohKey (keys %HoH)
{
    my $newHash = $HoH{$hohKey};
    print "Line Name: $hohKey\n";
    foreach my $key (keys %$newHash)
    {
        print "\t$key => ", $newHash->{$key}, "\n";
    }
}

Answer 4

每次从一行数据创建一个新哈希时，您都需要考虑一个唯一的密钥来将该数据存储在您的顶级哈希表中。

my $line = 1;
my %HoH;
while (<>) {
    my ($cell01, $cell02, $cell03, @etc) = split /,/;
    my $newHash = { cell01 => $cell01, cell02 => $cell02, ... };
    my $key = "line$line";
    $HoH{$key} = $newHash;
    $line++;
}

现在keys(%HoH)将返回"line1","line2","line3",...之类的（未排序的）列表。
$HoH{"line5"}会返回对文件第5行数据的引用 %{$HoH{"line7"}}是一种丑陋的语法，但它会返回数据的哈希表从第7行开始 $HoH{"line14"}{"cell02"}可用于获取特定数据。

如何在脚本执行期间为已知Hash创建和添加匿名哈希？

4 个答案: