arrays - 如何在 Perl 中创建二维数组？

Question

我正在尝试在 Perl 中创建一个二维数组

我的代码:

my @wordsList=();
my @words=();

for ($id=0; $id<=@language.length; $id++)
{

        my $eng = $db->selectall_arrayref("select word from words 
                                                    left outer join language
                                                    on words.languageId = language.languageId
                                                    where words.languageId = $id
                                                    ;");


        foreach $eng(@$eng)
        {   
        my($word) = @$eng;
        $ref_to_Array->[$id][$word] = @words($id,$word);

            }
                return $words($id, $word);
}

$wordsList= NextWords();
print $wordsList;

它返回非..因为我想返回二维数组。

更新

我仍然很困惑，因为当我执行查询时，它给了我一个单词列表，例如:

select word from words where language_id = 1 
(1=english, 2 - chinese, 3 - french) 

我正在通过语言使用 for 循环，以便从数据库中获取所有单词

问题是我想循环并希望将数组自动添加到二维数组中。

Answer 1

地点 use warnings; use strict;在您编写的每个程序的顶部。这两个 pragma 将为您捕获许多错误。

您不能使用 (...) 访问数组后缀。该构造用于调用函数 mysub(...)或 $mysubref->(...) .要访问数组元素，请使用后缀 [ index ] .而在 Perl 中，多维数组需要一对 [...]对于每个级别。这是因为二维数组只是一个数组，其中每个元素也是一个数组。

my @array = ([1, 2, 3], [4, 5, 6], [7, 8, 9]);

my $top_left     = $array[0][0];  # 1
my $bottom_right = $array[2][2];  # 9

print "@$_\n" for @array;

1 2 34 5 67 8 9

You can learn more about Perl's data structures and the rest of Perl at perldoc.perl.org. Here are a few direct links:

• arrays of arrays: perllol
• complex data structures: perldsc
• general language reference

Finally, @language.length does not do what you think it does. It is taking @language in scalar context, which is its length as a number and then concatenating it with length($_). The resulting expression is something like (scalar @language) . length($_). Since the <= operator imposes scalar context on its arguments, you could simply write $id <= @language. However, Perl provides you with a more natural way of writing this type of loop:

for my $id (0 .. @language) {...}

或者

对于我的 $id (0 .. $#language) {...}
如果你是真的意思 $id < @language自 $language[scalar @language]是数组末尾的一个元素。