Discussion of Perl's three built-in data types: scalars, arrays of scalars, and associative arrays of scalars, known as "hashes". At your command-line: perldoc perldata
perldata - Perl data types
perldsc - Perl Data Structures Cookbook
Questions tagged [perl-data-structures]
388 questions
8
votes
2 answers
Search for hash in an array by value
I have a function which extracts Excel data into an array of hashes like so:
sub set_exceldata {
my $excel_file_or = '.\Excel\ORDERS.csv';
if (-e $excel_file_or) {
open (EXCEL_OR, $excel_file_or) || die("\n can't open…
DidYouJustDoThat
8
votes
5 answers
Dynamically/recursively building hashes in Perl?
I'm quite new to Perl and I'm trying to build a hash recursively and getting nowhere. I tried searching for tutorials to dynamically build hashes, but all I could find were introductory articles about hashes. I would be grateful if you point me…
Gaurav Dadhania
- 5,167
- 8
- 42
- 61
8
votes
6 answers
How do I create a hash of hashes in Perl?
Based on my current understanding of hashes in Perl, I would expect this code to print "hello world." It instead prints nothing.
%a=();
%b=();
$b{str} = "hello";
$a{1}=%b;
$b=();
$b{str} = "world";
$a{2}=%b;
print "$a{1}{str} $a{2}{str}";
I…
Mike
- 58,961
- 76
- 175
- 221
7
votes
4 answers
Create combinations from elements in an array
I have an array reference like below:
my $strings = [qw(a b c d)];
I want to form all possible combination and create an array of array as:
my $output = [qw(qw([a],[b],[c],[d],[a,b],[a,c],[a,d],[b,c],[b,d],[c,d], …
questionar
- 274
- 2
- 18
7
votes
1 answer
use of perl's eq operator changes type of the arguments
I made this script to check how scalars change when accidently using 'eq' instead of '==' and vice versa. Using '==' on strings changes nothing but using 'eq' on numbers makes the scalar change somehow. Here comes the code:
#!/usr/bin/perl
use…
Manne Tallmarken
- 119
- 6
7
votes
3 answers
Convert string "a.b.c" to $hash->{a}->{b}->{c} in Perl
I've dynamic nested hash-refs like this:
my $hash = { 'a' => { 'b' => { 'c' => 'value' } } };
I want to set the value of c to 'something' by allowing the user to input "a.b.c something".
Now getting the value could be done like this:
my $keys =…
agranig
- 129
- 1
- 7
6
votes
3 answers
Perl multi-dimensional table with headers
I'm trying to implement a multi-dimensional table with headers.
Here's an example for 2D:
< dimension1 >
/\ 'column0' 'column1'
dimension0 'row0' data00 data10
\/ 'row1' data01 …
Giovanni Funchal
- 8,934
- 13
- 61
- 110
6
votes
1 answer
What kind of data format is this?
I have a bunch of data files of the following form:
("String"
:tag1 (value)
:tag2 (value2)
:tag3 (
:nested_tag1 (foo)
:nested_tag2 (
:nested2_tag1 (
: ( nested3_tag1
…
wawawawa
- 431
- 3
- 12
6
votes
2 answers
Can references be made without declaring a variable first?
I have this code that works
my @new = keys %h1;
my @old = keys %h2;
function(\@new, \@old);
but can it be done without having to declare variables first?
function must have its arguments as references.
Sandra Schlichting
- 25,050
- 33
- 110
- 162
6
votes
1 answer
Including Hashes within Hashes in Perl
G'Day,
I'm currently working on creating big hashes from a lot of smaller hashes. Let's say that these smaller hashes are defined in a file each, and then can be included by the bigger hash.
For eg, let's look at some small hashes
File…
Gaurav Dadhania
- 5,167
- 8
- 42
- 61
6
votes
7 answers
How can I merge several hashes into one hash in Perl?
In Perl, how do I get this:
$VAR1 = { '999' => { '998' => [ '908', '906', '0', '998', '907' ] } };
$VAR1 = { '999' => { '991' => [ '913', '920', '918', '998', '916', '919', '917', '915', '912', '914' ] } };
$VAR1 = { '999' => { '996' => [] } };…
Nick
- 191
- 1
- 9
6
votes
4 answers
How can I create a nested hash as a constant in Perl?
I want to do, in Perl, the equivalent of the following Ruby code:
class Foo
MY_CONST = {
'foo' => 'bar',
'baz' => {
'innerbar' => 'bleh'
},
}
def some_method
a = MY_CONST[ 'foo' ]
end
end
# In some other file which…
Pistos
- 23,070
- 14
- 64
- 77
6
votes
2 answers
Perl serializing and Deserializing hash of hashes
I am trying to serialize a hash of hashes and then deserializing it to get back the original hash of hashes ..the issue is whenever i deserialize it ..it appends an autogenerated $var1 eg.
original hash
%hash=(flintstones => {
husband =>…
user1547285
- 63
- 1
- 3
6
votes
4 answers
Adding value to array if condition is fulfilled
I am building an array of hashes of arrays
my @array = (
{label => 'first hash'},
{label => 'second hash',
innerarray => [
{label => 'first inner hash'},
{label => 'second inner hash'},
]
},
);
Is there a way…
Pit
- 1,448
- 1
- 18
- 26
5
votes
2 answers
How do I process a partial order of tasks concurrently using Perl?
I have a partially ordered set of tasks, where for each task all of the tasks that are strictly before it in the partial order must be executed before it can be executed. I want to execute tasks which are not related (either before or after one…
lexicalscope
- 7,158
- 6
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- 57