Hi all,
I recently had one requirement where I needed to get the key in a hash on
the basis of supplied value.
There is one additional information that there is one to one mapping between
the keys and the values.
I was able to do that by defining a extra array and hash variables as shown
in the program below but I feel this approach will not work for all
scenarios like :-
1. When the value of a particular key is undef in the original hash.
2. When there are nested data structures.
I have pasted the program as well as the output over here.
*Prompt#* *cat test_hash_reverse.pl*
#! /usr/bin/perl
use strict;
use warnings;
my %h1 =
(
"N" => "North",
"E" => "East",
"W" => "West",
"S" => "South",
"C" => "Central"
);
print "The Hash h1 is printed below :-\n";
foreach my $var1 (keys %h1)
{
print "\t[$var1] => [$h1{$var1}]\n";
}
my @arr1 = %h1;
print "The Array arr1 as initialized from the Hash h1 is printed below
:-\n";
print "@arr1\n";
my @arr2 = reverse (@arr1);
print "The Array arr2 as initialized from the reverse of the Array arr1 is
printed below :-\n";
print "@arr2\n";
my %h2 = @arr2;
print "The Hash h2 as initialized from the Array arr2 is printed below
:-\n";
foreach my $var2 (keys %h2)
{
print "\t[$var2] => [$h2{$var2}]\n";
}
*Prompt #* *perl test_hash_reverse.pl*
The Hash h1 is printed below :-
[S] => [South]
[W] => [West]
[C] => [Central]
[N] => [North]
[E] => [East]
The Array arr1 as initialized from the Hash h1 is printed below :-
S South W West C Central N North E East
The Array arr2 as initialized from the reverse of the Array arr1 is printed
below :-
East E North N Central C West W South S
The Hash h2 as initialized from the Array arr2 is printed below :-
[West] => [W]
[Central] => [C]
[South] => [S]
[North] => [N]
[East] => [E]
*Prompt #*
Thanks & Regards,
Amit Saxena
