Getting values from a Hash from user input

blueblue has asked for the wisdom of the Perl Monks concerning the following question:

Hi, So what I am trying to do is print the values from a hash based on user input. So the user input needs to match the key in order to print the associated value. so I was thinking it would go something like this:

use strict;
use warnings;

my %words = ('hello' => 'world');

print 'type a word: '
chomp(my $inData = <>);

if($inData eq (keys %words){
   print 'value: ', values %words;
}
[download]

I looking for others ways to approach this, any input would be a lot of help thanks!

Comment on Getting values from a Hash from user input Download Code

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Re: Getting values from a Hash from user input by GrandFather (Saint) on Nov 21, 2013 at 20:31 UTC
`if (exists $words{$inData}) {` [download] See exists. True laziness is hard work	[reply] [d/l]
Re: Getting values from a Hash from user input by Kenosis (Priest) on Nov 21, 2013 at 21:10 UTC
Another way is to use Perl's defined-or operator (`//`): `use strict; use warnings; my %words = ( 'hello' => 'world' ); print 'type a word: '; chomp( my $inData = <> ); print $words{$inData} // "Key '$inData' doesn't exist.\n";` [download] If the key's defined, it's associated value will be printed, otherwise the 'default' string will be printed. Hope this helps! Edit: `//=` -> `//`. Thank you, Eily.	[reply] [d/l] [select]
Re^2: Getting values from a Hash from user input by Eily (Monsignor) on Nov 21, 2013 at 21:33 UTC
The defined-or operator is just //. `$lvalue //= "value";` actually means `$lvalue = "value" unless defined $lvalue;`. This means that you actually write "Key '$inData' doesn't exist.\n" in the hash : `use Data::Dumper; my %words = ( 'hello' => 'world' ); print 'type a word: '; chomp( my $inData = <> ); print $words{$inData} //= "Key '$inData' doesn't exist.\n"; print Dumper \%words;` [download] `type a word: Bonjour Key 'Bonjour' doesn't exist. $VAR1 = { 'hello' => 'world', 'Bonjour' => 'Key \'Bonjour\' doesn\'t exist. ' };` [download] You meant `print $words{$inData} // "Key '$inData' doesn't exist.\n";` which works fine as long as undef isn't a valid value.	[reply] [d/l] [select]
Re^3: Getting values from a Hash from user input by Kenosis (Priest) on Nov 21, 2013 at 21:36 UTC
Thanks for this catch! Corrected...	[reply]
Re^4: Getting values from a Hash from user input by blueblue (Initiate) on Nov 21, 2013 at 22:01 UTC
Re: Getting values from a Hash from user input by blueblue (Initiate) on Nov 22, 2013 at 14:46 UTC
Thanks for the help guys, appreciate it.	[reply]