如何在perl中正确创建和循环三维数组？

Question

我有一个算法，选择一个3D数组中的单元格，然后读取或写入数据，这是另一个3D数组的引用。把它想象成一个“我的世界”算法。 问题是我不知道如何在Perl中创建一个像这样的数据结构：@ 3darray（x，y，z）= value 你能帮我吗？

Answer 1

如果我理解正确：

use Data::Dumper; 

my ($x, $y, $z) = (1, 2, 3); 
my @array = map [map [map 0, 1..$z], 1..$y], 1..$x; 

print Dumper \@array; 

输出：

$VAR1 = [ 
      [ 
      [ 
       0, 
       0, 
       0 
      ], 
      [ 
       0, 
       0, 
       0 
      ] 
      ] 
     ]; 

然而，没有必要使这个结构提前，因为Perl通过自动激活为您创建它（请参阅参考资料进一步下跌）当您访问嵌套结构中的元素时：

use Data::Dumper; 

my @array; 
$array[0][0][2] = 3; 

print Dumper \@array; 

输出：

$VAR1 = [ 
      [ 
      [ 
       undef, 
       undef, 
       3 
      ] 
      ] 
     ]; 

从perlglossary：

autovivification 

A Greco-Roman word meaning "to bring oneself to life". In Perl, storage locations 
(lvalues) spontaneously generate themselves as needed, including the creation of 
any hard reference values to point to the next level of storage. The assignment 
$a[5][5][5][5][5] = "quintet" potentially creates five scalar storage locations, 
plus four references (in the first four scalar locations) pointing to four new 
anonymous arrays (to hold the last four scalar locations). But the point of 
autovivification is that you don't have to worry about it. 

至于循环，如果你需要索引：

for my $i (0 .. $#array) { 
    for my $j (0 .. $#{$array[$i]}) { 
     for my $k (0 .. $#{$array[$i][$j]}) { 
      print "$i,$j,$k => $array[$i][$j][$k]\n"; 
     } 
    } 
} 

否则：

for (@array) { 
    for (@$_) { 
     for (@$_) { 
      print "$_\n"; 
     } 
    } 
}