Visit Our UNIX and Linux User Community


Confusion in hash


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Confusion in hash
# 1  
Old 09-06-2013
Confusion in hash

Hi folks,

If a declare a direct hash , then the hash element works fine.
Code:
my %test = ("test",1);
print %test;
print "\n";

Here in the above, the name of the hash is predeclared...

Suppose now I need to create the hash elements dynamically in the for loop.

Code:
$test="hash";
my ${$test}=("test",1);  ## assuming $test will be replaced by hash

But receiving an error message as below..

an't declare scalar dereference in "my" at hashtest.pl line 3, near "}="
xecution of hashtest.pl aborted due to compilation errors.

I have a requirement in which I need to create the hash elements in the loop based on some variables in array and I'm using "use strict" and "use warning pragmas" .

Could anyone please let me know how to create hash variables from the elements of array?

Thanks in advance ....

Last edited by scriptscript; 09-06-2013 at 09:41 AM..
# 2  
Old 09-06-2013
Code:
#! /usr/bin/perl

my @arr = ("key1", "key2", "key3");
my %hash = ();

foreach (@arr) {
    $hash{$_} = 1;
}

foreach (keys %hash) {
    print "$_ --> $hash{$_}\n";
}


Previous Thread | Next Thread
Test Your Knowledge in Computers #549
Difficulty: Medium
a = 10; is an example of a unary operation.
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Need to print hash of hash in table format

Hi, I have a hash of hash where it has name, activities and count i have data like this - $result->{$name}->{$activities} = $value; content of that are - name - robert tom cat peter activities - running, eating, sleeping , drinking, work i need to print output as below ... (3 Replies)
Discussion started by: asak
3 Replies

2. Shell Programming and Scripting

Dynamically parse BibTeX and create hash of hash

Hello gurus, Iam trying to parse following BibTex file (bibliography.bib): @book{Lee2000a, abstract = {Abstract goes here}, author = {Lee, Wenke and Stolfo, Salvatore J}, title = {{Data mining approaches for intrusion detection}}, year = {2000} } @article{Forrest1996, abstract =... (0 Replies)
Discussion started by: wakatana
0 Replies

3. Shell Programming and Scripting

Compare values of hashes of hash for n number of hash in perl without sorting.

Hi, I have an hashes of hash, where hash is dynamic, it can be n number of hash. i need to compare data_count values of all . my %result ( $abc => { 'data_count' => '10', 'ID' => 'ABC122', } $def => { 'data_count' => '20', 'ID' => 'defASe', ... (1 Reply)
Discussion started by: asak
1 Replies

4. Shell Programming and Scripting

Confusion with PS

Hello All, I have a problem in counting number of process getting run with my current script name.. Here it is ps -ef | grep $0 | grep -v grep This display just one line with the PID, PPID and other details when i print it in the script. But when I want to count the numbers in my... (11 Replies)
Discussion started by: sathyaonnuix
11 Replies

5. Shell Programming and Scripting

perl hash - using a range as a hash key.

Hi, In Perl, is it possible to use a range of numbers with '..' as a key in a hash? Something in like: %hash = ( '768..1536' => '1G', '1537..2560' => '2G' ); That is, the range operation is evaluated, and all members of the range are... (3 Replies)
Discussion started by: dsw
3 Replies

6. Shell Programming and Scripting

Perl Hash:Can not keep hash data in the same order that it was inserted

Can Someone explain me why even using Tie::IxHash I can not get the output data in the same order that it was inserted? See code below. #!/usr/bin/perl use warnings; use Tie::IxHash; use strict; tie (my %programs, "Tie::IxHash"); while (my $line = <DATA>) { chomp $line; my(... (1 Reply)
Discussion started by: jgfcoimbra
1 Replies

7. Shell Programming and Scripting

Assigning a hash to another hash key

Hello, I have a hash in hsh. I need to assign it to another hash globalHsh. I think the below statement does not work $globalHsh{$id} = %hsh; What is the right way to assign it? Thanks (3 Replies)
Discussion started by: rsanjay
3 Replies

8. Shell Programming and Scripting

Print Entire hash list (hash of hashes)

I have a script with dynamic hash of hashes , and I want to print the entire hash (with all other hashes). Itried to do it recursively by checking if the current key is a hash and if yes call the current function again with refference to the sub hash. Most of the printing seems to be OK but in... (1 Reply)
Discussion started by: Alalush
1 Replies

9. UNIX for Dummies Questions & Answers

'tr' confusion

Good day, everyone! Could anybody explain me the following situation. If I'm running similar script: Var="anna.kurnikova" Var2="Anna Kurn" echo $Var | tr -t "$Var" "$Var2" Why the output is : anna KurniKova instead of Anna Kurnikova? :confused: Thank you in advance for any... (2 Replies)
Discussion started by: Nafanja
2 Replies

10. Shell Programming and Scripting

Sed confusion

Hello all, I am trying to delete all the lines in a particular file having a pattern. The problem is that it has special characters and for some reason is not doing the job. For eg. src_file /home/test/filelist.txt :xxxx:ogog /home/test/RCH/ogogogg /home/test/RYHUJ/HHHH... (3 Replies)
Discussion started by: alfredo123
3 Replies

Featured Tech Videos