I found the data structure below somewhere on the Internet. What type of
data structure is it, and how do I access elements of it? For example,
how would I print FIRST_NAME?
-Thanks
$rec =
{
fields => {
'FIRST_NAME' => 0,
'LAST_NAME' => 1,
'ADDRESS' => 2,
},
encoding => [
[6, 18, 'C'],
[26, 1, 'C'],
[46, 8, 'D'],
],
};
In article
James Egan
> I found the data structure below somewhere on the Internet. What type of
> data structure is it, and how do I access elements of it? For example,
> how would I print FIRST_NAME?
>
> -Thanks
>
>
> $rec =
> {
> fields => {
> 'FIRST_NAME' => 0,
> 'LAST_NAME' => 1,
> 'ADDRESS' => 2,
> },
>
> encoding => [
> [6, 18, 'C'],
> [26, 1, 'C'],
> [46, 8, 'D'],
> ],
> };
print $rec->{fields}{FIRST_NAME}; #should print 0
also
print $rec->{encoding}[1][0]; #should print 26
cheers,
big
--
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all passionate authentic experiences will be appropriated, mishandled,
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you hate." Mr Jalopy quoting Hooptyrides (on jalopyjunktown.com)
James Egan wrote:
> I found the data structure below somewhere on the Internet. What type of
> data structure is it, and how do I access elements of it? For example,
> how would I print FIRST_NAME?
> $rec =
> {
> fields => {
> 'FIRST_NAME' => 0,
> 'LAST_NAME' => 1,
> 'ADDRESS' => 2,
> },
>
> encoding => [
> [6, 18, 'C'],
> [26, 1, 'C'],
> [46, 8, 'D'],
> ],
> };
$rec is a hash reference, the hash it addresses
"contains" an array and another hash, so $rec
is a reference to "hash of hash and array " (HoHaA)
fields is, as said, a hash reference and points to a hash,
encoding is an array reference in itself and points to
another "array of arrays" (AoA).
Access to fields:
print $rec->{fields}->{LAST_NAME};
which can be written as
print $rec->{fields}{LAST_NAME};
Access to encoding:
print $rec->{encoding}->[0]->[2]; # array[0][2], 'D'
which can be written as:
print $rec->{encoding}[0][2];
Regards
M.
On Sep 24, 8:33 pm, James Egan
> I found the data structure below somewhere on the Internet.
> What type of data structure is it, and how do I access elements
> of it? For example, how would I print FIRST_NAME?
> $rec =
> {
> fields => {
> 'FIRST_NAME' => 0,
> 'LAST_NAME' => 1,
> 'ADDRESS' => 2,
> },
>
> encoding => [
> [6, 18, 'C'],
> [26, 1, 'C'],
> [46, 8, 'D'],
> ],
> };
Buckle in. . .
$rec is a reference to a hash.
The hash that $rec references, known as %{$rec}, contains two key/
value pairs.
The first key listed in %{$rec} above is 'fields'. The value in %
{$rec} associated with the key 'fields', known as $rec->{fields}, is a
reference to a hash.
The hash that $rec->{fields} references, known as %{$rec->{fields}},
contains three key/value pairs.
The first key listed in %{$rec->{fields}} is 'FIRST_NAME'. The value
associated with this key, known as $rec->{fields}{FIRST_NAME}, is 0.
The second key listed in %{$rec} above is 'encoding'. The value in %
{$rec} associated with the key 'encoding', known as $rec->{encoding},
is a reference to an array.
The array that $rec->{encoding} references, known as @{$rec-
>{encoding}}, contains three values.
Each of the three values of @{$rec->{encoding}} are references to
arrays. The first of these values is $rec->{encoding}[0].
The array that $rec->{encoding}[0] references, known as @{$rec-
>{encoding}[0]}, contains three values: 6, 18, and 'C'.
You can access the second value, 18, of this array as: $rec->{encoding}
[0][1].
For further details and explanations, see the tutorials and references
in perldoc:
perldoc perlreftut
perldoc perllol
perldoc perldsc
Paul Lalli