如何在Perl中优雅地将用户输入转换为变量名？

Question

I want to use input from the user to pick a hash to operate on. Currently, I have this cumbersome code:

my ( %hash1, %hash2 );
print "Which hash to work with (1 or 2)? ";
my $which = <>;
chomp $which;
&do_something( %hash1 ) if $which == 1;
&do_something( %hash2 ) if $which == 2;

Is there a more elegant way to do this? I was thinking of using %{"hash$which"} , but that doesn't seem to work. I think

$which = "hash" . chomp $which;
&do_something( %{"$which"} );

would work, but is that the best way to do it?

Thanks for the help, especially since this is my first SO post.

Answer 1

Why it's stupid to use a variable as a variable name

You want

my @hashes;
print "Which hash to work with (1 or 2)? ";
my $which = <>;
chomp $which;
do_something( %{ $hashes[$which] } );

Just in case you don't know, always use use strict; use warnings; use strict; use warnings; .

Answer 2

What you are looking for is called a "symbolic reference" in the perl world. The use of symbolic references is strongly discouraged .

Why not add another level of indirection?

my $hash = {
    user_opt1 => {
        foo => 'bar',
    },
    user_opt2 => {
        foo => 'baz',
    },
};