如何从另一个包perl访问我的％hash中的元素值

Question

我在包名称中有一个哈希：./ lib.pm

#!/usr/bin/perl -w
use strict;
use warnings;

package lib;

#my %hash = (
our %hash = (
    Addr =>
    {
        'aa' => 0x11223344,
        'bb' => 0x55667788,
        'cc' => 0xaabbccdd,
    },
);

我试图通过以下几种方式从另一个包访问所有元素：./ check.pm

#!/usr/bin/perl -w
use strict;
use warnings;

use Cwd;
my $dir = getcwd;
unshift( @INC, $dir );
require lib;

print "========================\n";
print "1: $lib::hash{Addr}{'aa'}\n";
print "2: $lib::hash{Addr}{'bb'}\n";
print "3: $lib::hash{Addr}{'cc'}\n";

print "========================\n";
printf (sprintf("%8X\n", $lib::hash{Addr}{aa}));
printf (sprintf("%8X\n", $lib::hash{Addr}{bb}));
printf (sprintf("%8X\n", $lib::hash{Addr}{cc}));

print "========================\n";
my ($Address_a, $Address_b, $Address_c);
my (@Address_a, @Address_b, @Address_c, @names);
$Address_a = sprintf("%8X", $lib::hash{Addr}{'aa'});
$Address_b = sprintf("%8X", $lib::hash{Addr}{'bb'});
$Address_c = sprintf("%8X", $lib::hash{Addr}{'cc'});
@Address_a = ( $Address_a =~ m/../g );
@Address_b = ( $Address_b =~ m/../g );
@Address_c = unpack("(A2)*", $Address_c);

printf "========================\n";
printf ("@Address_a \t\n");
printf ("@Address_b \t\n");
printf ("@Address_c \t\n");

printf "========================\n";
printf ("$Address_a[0], $Address_a[1], $Address_a[2], $Address_a[3]\n");
printf ("$Address_b[0], $Address_b[1], $Address_b[2], $Address_b[3]\n");
printf ("$Address_c[0], $Address_c[1], $Address_c[2], $Address_c[3]\n");

我通常得到了结果：

========================
1: 287454020
2: 1432778632
3: 2864434397
========================
11223344
55667788
AABBCCDD
========================
========================
11 22 33 44
55 66 77 88
AA BB CC DD
========================
11, 22, 33, 44
55, 66, 77, 88
AA, BB, CC, DD

但是当我将哈希声明的方式从“我的％哈希”更改为“我的％哈希”时，结果就消失了：

========================
Use of uninitialized value in concatenation (.) or string at ./check.pm line 10.
1:
Use of uninitialized value in concatenation (.) or string at ./check.pm line 11.
2:
Use of uninitialized value in concatenation (.) or string at ./check.pm line 12.
3:
========================
Use of uninitialized value in sprintf at ./check.pm line 14.
       0
Use of uninitialized value in sprintf at ./check.pm line 15.
       0
Use of uninitialized value in sprintf at ./check.pm line 16.
       0
========================
Use of uninitialized value in sprintf at ./check.pm line 20.
Use of uninitialized value in sprintf at ./check.pm line 21.
Use of uninitialized value in sprintf at ./check.pm line 22.
========================
          0
          0
    0
========================
  ,   ,   ,  0
  ,   ,   ,  0
, , ,  0

从“my％hash”获取数据时是否需要进行任何更改？

Answer 1

my声明一个词法变量，你不能扩展词法变量的范围，即在包外面共享它。

为什么你不能使用our变量？

您不能共享词法变量，但可以共享其值。例如，您可以在包中公开值的闭包：

#!/usr/bin/perl
use warnings;
use strict;

{   package MyLib;

    my %hash = (
        Addr => {
            aa => 0x11223344,
            bb => 0x55667788,
            cc => 0xaabbccdd,
        },
    );
    sub get_hash { %hash }

}


my %hash = MyLib::get_hash();
print "========================\n";
print "1: $hash{Addr}{'aa'}\n";
print "2: $hash{Addr}{'bb'}\n";
print "3: $hash{Addr}{'cc'}\n";