Extracting single element from array to be printed in a one liner hash

wildguess123 has asked for the wisdom of the Perl Monks concerning the following question:

Hi all. I have the following code, #!/usr/bin/perl -w

open(FILEHANDLE,'movies.txt');

@array2 =<FILEHANDLE>;

close FILEHANDLE;

open(FILEHANDLE2,'fruits.txt');

@array3 =<FILEHANDLE2>;

close FILEHANDLE2;

foreach $movie (@array2) {

chomp($movie);

$data {$movie} = "movies";

}

foreach $fruits (@array3) {

chomp($fruits);

$data {$fruits} = "fruits";

}

do{

print "Please enter a string \n";

chomp($input = <STDIN>);

foreach $key (keys(%data)){

if($key{$data} eq $input){

print "$input is a $data{$key}\n";

}

} while ($input ne 0); The elements in movies.txt is the following:

the blind side

iron man

star trek

gi joe The elements in fruits.txt is the following:

orange

apple

pear

water melon

This is what I want to achieve. For example, when the user enters apples, It would be printed : apples is a fruits, and thats it. Another example, when I enter gi joe,it would print: gi joe is a movie. Now , I am facing the following problems, when I enter apples when the program ask the user to enter the string, it would not appear anything and would prompt us to enter again. How should I edit my code to fulfill the following above? Thanks!

Comment on Extracting single element from array to be printed in a one liner hash

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Re: Extracting single element from array to be printed in a one liner hash by toolic (Bishop) on May 20, 2014 at 13:55 UTC
if($key{$data} eq $input){ If you had used strict (tip #1 from the Basic debugging checklist), you'd have gotten an error regarding the `%key` variable. Perhaps you meant... `if($data{$key} eq $input){` [download] See also Writeup Formatting Tips. Use "code" tags.	[reply] [d/l] [select]
Re: Extracting single element from array to be printed in a one liner hash by Lotus1 (Vicar) on May 20, 2014 at 13:55 UTC
`foreach $key (keys(%data)){ if($key{$data} eq $input){` [download] It looks like you swapped your hash and iterator variable. `$key{$data}`: there are no hashes called key available. If you had used strict it would have given you an error about it. Update: Since `$data{$key}` will always equal "movies" or "fruits" I think you meant to do this: `foreach $key ( keys(%data) ){ if($key eq $input){` [download]	[reply] [d/l] [select]
Re^2: Extracting single element from array to be printed in a one liner hash by wildguess123 (Initiate) on May 20, 2014 at 14:02 UTC
I got the following error when u changed the foreach loop to yours: Please enter a string apple Use of uninitialized value $data in hash element at p3task6.pl line 30 +, <STDIN> line 2. Use of uninitialized value in string eq at p3task6.pl line 30, <STDIN> + line 2. Use of uninitialized value $data in hash element at p3task6.pl line 30 +, <STDIN> line 2. Use of uninitialized value in string eq at p3task6.pl line 30, <STDIN> + line 2. Use of uninitialized value $data in hash element at p3task6.pl line 30 +, <STDIN> line 2. Use of uninitialized value in string eq at p3task6.pl line 30, <STDIN> + line 2. Use of uninitialized value $data in hash element at p3task6.pl line 30 +, <STDIN> line 2. Use of uninitialized value in string eq at p3task6.pl line 30, <STDIN> + line 2. Use of uninitialized value $data in hash element at p3task6.pl line 30 +, <STDIN> line 2. Use of uninitialized value in string eq at p3task6.pl line 30, <STDIN> + line 2. Use of uninitialized value $data in hash element at p3task6.pl line 30 +, <STDIN> line 2. Use of uninitialized value in string eq at p3task6.pl line 30, <STDIN> + line 2. Use of uninitialized value $data in hash element at p3task6.pl line 30 +, <STDIN> line 2. Use of uninitialized value in string eq at p3task6.pl line 30, <STDIN> + line 2. Use of uninitialized value $data in hash element at p3task6.pl line 30 +, <STDIN> line 2. Use of uninitialized value in string eq at p3task6.pl line 30, <STDIN> + line 2. Please enter a string [download]	[reply] [d/l]
Re^3: Extracting single element from array to be printed in a one liner hash by moritz (Cardinal) on May 20, 2014 at 14:07 UTC
To get rid of the warnings, you can write `if (defined $data{$key} && $data{$key} eq $input) { ... }` [download] Also, please do read, understand and apply Writeup Formatting Tips. Perl 6 - the future is here, just unevenly distributed	[reply] [d/l]
Re^4: Extracting single element from array to be printed in a one liner hash by Lotus1 (Vicar) on May 20, 2014 at 17:47 UTC