如何从Perl哈希引用设置标量列表? [英] How to set a list of scalars from a perl hash ref?

问题描述

如何从perl哈希中设置标量列表?

How do I set a list of scalars from a perl hash?

use strict;
my $my_hash = { field1=>'val1', field2=>'val2', field3=>'val3', };
my ($field1,$field2,$field3) = %{$my_hash}{qw(field1 field2 field3)};

print "field1=$field1\nfield2=$field2\nfield3=$field3\n";

推荐答案

您正在寻找散列片，在您的情况下，看起来像这样:

You're looking for a hash slice which in your case would look like this:

my ($field1,$field2,$field3) = @{$my_hash}{qw(field1 field2 field3)};

或类似这样:

my ($field1,$field2,$field3) = @$my_hash{qw(field1 field2 field3)};

如果我们简化一些事情，以便您使用的是直接哈希而不是hash-ref，则可以消除一些干扰，语法看起来会更清晰:

If we simplify things so that you're working with a straight hash rather than hash-ref, we can remove some of the noise and the syntax will look a bit clearer:

my %my_hash = ( field1=>'val1', field2=>'val2', field3=>'val3' );
my ($field1, $field2, $field3) = @my_hash{  qw(field1 field2 field3)  };
# we want an array/list ---------^       ^  ^
# but my_hash is a hash -----------------/  |
# and we want these keys (in this order) ---/
# so we use a qw()-array

然后我们可以通过以通常的方式将哈希替换为哈希引用来获取您的$my_hash哈希引用版本.

Then we can get to your $my_hash hash-ref version by replacing the hash with a hash-ref in the usual way.

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