Questions tagged [hash-reference]
11 questions
69
votes
4 answers
What's the difference between a hash and hash reference in Perl?
I would like to properly understand hashes in Perl. I've had to use Perl intermittently for quite some time and mostly whenever I need to do it, it's mostly related to text processing.
And everytime, I have to deal with hashes, it gets messed up. I…
user855
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4
votes
4 answers
What does `$hash{$key} |= {}` do in Perl?
I was wrestling with some Perl that uses hash references.
In the end it turned out that my problem was the line:
$myhash{$key} |= {};
That is, "assign $myhash{$key} a reference to an empty hash, unless it already has a value".
Dereferencing this…
slim
- 40,215
- 13
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- 127
3
votes
2 answers
Perl Creating hash reference and looping through one element from each branch at a time
As a beginner I have what I think is a rather complicated problem I am hoping someone could help with.
I have the following text file (tab delminated)...
FILE1.txt
Dog Big
Dog Medium
Dog Small
Rabbit Huge
Rabbit …
yonetpkbji
- 1,019
- 2
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1
vote
2 answers
Does returning a ref to a hash declared in subroutine causes memory leak?
Is using my %data; below okay or should I switch to my $data={}; ?
#!/usr/bin/perl -wT
use strict;
use JSON;
sub makeJson {
my %data;
$data{kib} = 1;
$data{games} = {
0 => [],
1 => [qw(a b c…
Alexander Farber
- 21,519
- 75
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1
vote
3 answers
How to display the special value always at top while sorting?
I used the below code to sort values and display it as a dropdown in a Perl form page And I need to display a certain value always at the top of the sorted list, how to do that?
values= [sort {$a<=>$b and $orig->{$a} cmp $orig->{$b}} keys %$orig]…
KnowNothing
- 69
- 7
1
vote
1 answer
Error when accessing array of hashes
I'm trying to generate a list of hashes, interacting with the user using the following script:
use strict;
use warnings;
my $KEY_1 = "one";
my $KEY_2 = "two";
sub generateHash{
my ($value1, $value2) = (@_);
$value2 = $value1 + 5.0;
…
Hellzzar
- 185
- 1
- 9
1
vote
2 answers
Accessing args in Perl Hash Ref
$self->doSomething({
record => $record,
listing => [ $foo, $bar, $baz ],
passedargs => { something => $val, another => $val2 }
});
accessing args within a hashref.
So if I wanted to access record I would
my $record =…
zachary adams
- 83
- 11
1
vote
3 answers
Perl nested data structures
I'm having trouble wrapping my brain around the data structure that is being returned...What I need to do is inspect the results, and modify a field if it is a HASH. Within 'results' any KEY that is a HASH with a KEY of 'null' and value of '1'…
narddawg314
- 13
- 2
1
vote
2 answers
How can I update a hash value using a hash reference in Perl?
Is there a way to update a value in a hash using a hash reference that points to the hash value?
My hash output looks like this:
'Alternate' => {
'free' => '27.52',
'primary' => 'false',
'used' => '0.01',
'name'…
user2063351
- 503
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0
votes
3 answers
How can I iterate through nested hash of hash without knowing its key?
I have a hash of hashes, that is, hash and hash references in my data structure. Can I iterate through the deepest hash when I only have the main hash name and no key of the deepest hash?
my %gates_info=(
'order' => {
'nand' => {
…
P_Z
- 199
- 2
- 8
-4
votes
1 answer
Passing hash reference to multiple functions in Perl
I have following code in Perl where a hash reference is passed from main function to func1 and then to func2. In func2 hash is updated. I want to access the updated hash in main function. Also there is a while loop in main function and i am…
Sam
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