我正在尝试添加一个哈希条目和一个新的,更新的哈希条目,它们来自相同的馈线哈希和原始数据。
然而,当我更新第二个条目的数据时…它破坏了原始条目……即使数据没有改变……只有当两者都是从相同的馈线哈希条目分配时,它才会发生变化。
下面是我为测试这个问题而创建的测试程序中的一个示例子程序-它使用Tk作为输出…
sub hash_issue {
my %feeder = ();
my %global = ();
my %personal = ();
my $key = 'John';
my $new_key = 'Johnathan';
$feeder{$key}{First_Name} = 'John';
$feeder{$key}{Last_Name} = '';
$feeder{$key}{Address} = '123 Main Street';
$feeder{$key}{City} = 'Springfield';
$feeder{$key}{State} = '';
$feeder{$key}{Zip} = '';
$feeder{$key}{Is_Registered} = 0;
$global{$key} = $feeder{$key};
$main->Output->Append("First Name = $global{$key}{First_Name} Last Name = $global{$key}{Last_Name} Address = $global{$key}{Address} Registered = $global{$key}{Is_Registered}rn");
$global{$new_key} = $feeder{$key};
$global{$new_key}{First_Name} = $new_key;
$global{$new_key}{Is_Registered} = 1;
$main->Output->Append("First Name = $global{$key}{First_Name} Last Name = $global{$key}{Last_Name} Address = $global{$key}{Address} Registered = $global{$key}{Is_Registered}rn");
$main->Output->Append("First Name = $global{$new_key}{First_Name} Last Name = $global{$new_key}{Last_Name} Address = $global{$new_key}{Address} Registered = $global{$new_key}{Is_Registered}rn");
}
输出如下:
名= John姓= Address = 123 Main Street Registered = 0
名= Johnathan姓= Address = 123 Main Street Registered = 1
名= Johnathan姓= Address = 123 Main Street Registered = 1
(添加额外的行来清理post…)
我如何修改它以避免破坏原始条目…REAL代码包含子哈希的更多键。
问题就在这里
$global{$new_key} = $feeder{$key};
这只复制引用。如果你想要一个真正的副本,你需要克隆你的数据。
use Clone qw( clone );
$global{$new_key} = clone( $feeder{$key} );
请检查以下代码片段是否符合您的问题。
从你的描述中我的理解是,你试图创建新的哈希%global
(以$new_key
为键),复制哈希%feeder
的值,然后改变其中的一些值。
注意:%global
变量在子程序中的声明有些混乱
use strict;
use warnings;
use feature 'say';
hash_issue();
sub hash_issue {
my(%feeder, %global);
my $key = 'John';
my $new_key = 'Johnathan';
my @fields = (
'First_Name',
'Last_Name',
'Address',
'City',
'State',
'Zip',
'Is_Registered'
);
my @values = (
'John',
'',
'123 Main Street',
'Springfield',
'',
'',
0
);
@{$feeder{$key}}{@fields} = @values;
@{$global{$new_key}}{@fields} = @{$feeder{$key}}{@fields};
speak_out($key, %feeder);
speak_out($new_key, %global);
$global{$new_key}{First_Name} = $new_key;
$global{$new_key}{Is_Registered} = 1;
speak_out($new_key, %global);
}
sub speak_out {
my $key = shift;
my $data = shift;
say "
Key = $key
------------------------------------
First Name = $data->{$key}{First_Name}
Last Name = $data->{$key}{Last_Name}
Address = $data->{$key}{Address}
Registered = $data->{$key}{Is_Registered}
";
}
输出
Key = John
------------------------------------
First Name = John
Last Name =
Address = 123 Main Street
Registered = 0
Key = Johnathan
------------------------------------
First Name = John
Last Name =
Address = 123 Main Street
Registered = 0
Key = Johnathan
------------------------------------
First Name = Johnathan
Last Name =
Address = 123 Main Street
Registered = 1
参考文献:Perl - Slices