Re: dereferencing an array - Pt 2
Short answer: $profit{ $facet }{ $term }{ $resource } = $url;
Example:
#!perl
use strict;
use warnings;
use Data::Dumper;
$Data::Dumper::Terse++;
$Data::Dumper::Indent--;
my %profit;
while( DATA ) {
chomp;
my( $resource, $url, $term, $facet ) = split /,/;
$profit{ $facet }{ $term }{ $resource } = $url;
}
print Dumper \%profit;
__DATA__
asto magazine,http://oxford.edu,astronomy,subjects
stars r us,http://websters.com,astronomy,subjects
telescope world,http://telescope.com,astronomy,subjects
2 + 2 = 4,http://catalog.nd.edu,mathematics,subjects
math library,http://worldcat.com,mathematics,subjects
und,http://catalog.nd.edu,catalogs,tools
worldcat,http://worldcat.com,catalogs,tools
websters,http://websters.com,dictionaries,tools
oxford,http://oxford.edu,dictionaries,tools
On 2/10/06, Eric Lease Morgan [EMAIL PROTECTED] wrote:
On Feb 10, 2006, at 5:41 PM, Bruce Van Allen wrote:
foreach my $facet_key (keys %facets) {
print $facet_key\n;
my %sub_hash= %{ $facets{$facet_key} };
foreach my $sub_key (keys %sub_hash) {
print \t$sub_key\n;
my %inner_hash= %{ $sub_hash{$sub_key} };
foreach my $inner_key (keys %inner_hash) {
print \t\t$inner_key - $inner_hash{$inner_key}\n;
}
}
}
This has been VERY helpful, and I appreciate the assistance. Now I
need to programatically build the hash.
I have this sample data structure:
my %profile = (
'subjects' = {
'astronomy' = {
'telescope world' = 'http://telescope.com',
'stars r us' = 'http://websters.com',
'asto magazine' = 'http://oxford.edu'
},
'mathematics' = {
'2 + 2 = 4' = 'http://catalog.nd.edu',
'math library' = 'http://worldcat.com'
}
},
'tools' = {
'dictionaries' = {
'websters' = 'http://websters.com',
'oxford' = 'http://oxford.edu'
},
'catalogs' = {
'und' = 'http://catalog.nd.edu',
'worldcat' = 'http://worldcat.com'
}
}
);
I use the followign code, based on the good work of Bruce, to
traverse %profile and output a set of nested HTML lists. It works for
any size of %profile. Fun!
print ul;
foreach my $facet (sort(keys(%profile))) {
print li$facet;
my %facets = %{$profile{$facet}};
print ul;
foreach my $term (sort(keys(%{$profile{$facet}}))) {
print li$term;
my %terms = %{$facets{$term}};
print ol;
foreach my $resource (sort(keys(%terms))) {
print lia href='$facets{$term}{$resource}'$resource/
a/li;
}
print /ol;
print /li;
}
print /ul;
print /li;
}
print /ul;
I now need to build %profile programatically. As I loop through a set
of information resources I can determine the following values:
1. resource name (ex: telescope world)
2. URL (ex: http://telescope.com)
3. term (ex: astronomy)
4. facet (ex: subjects)
Given these values, how can I build %profile?
--
Eric Perl Data Structures !R My Forte Morgan
Re: dereferencing an array - Pt 2
On Feb 11, 2006, at 8:16 AM, Brad Baxter wrote:
I have this sample data structure:
my %profile = (
'subjects' = {
'astronomy' = {
'telescope world' = 'http://telescope.com',
'stars r us' = 'http://websters.com',
'asto magazine' = 'http://oxford.edu'
},
'mathematics' = {
'2 + 2 = 4' = 'http://catalog.nd.edu',
'math library' = 'http://worldcat.com'
}
},
'tools' = {
'dictionaries' = {
'websters' = 'http://websters.com',
'oxford' = 'http://oxford.edu'
},
'catalogs' = {
'und' = 'http://catalog.nd.edu',
'worldcat' = 'http://worldcat.com'
}
}
);
I now need to build %profile programatically. As I loop through a set
of information resources I can determine the following values:
1. resource name (ex: telescope world)
2. URL (ex: http://telescope.com)
3. term (ex: astronomy)
4. facet (ex: subjects)
Given these values, how can I build %profile?
Short answer: $profile{ $facet }{ $term }{ $resource } = $url;
Wow! Perfect!!
I have been able to take what Jonathan Gorman, Bruce Van Allen, and
Brad Baxter have given me and incorporate it into a the beginnings of
a patron-specific interface of MyLibrary. In MyLibrary patrons can be
created and cataloged with facet/term combinations -- a controlled
vocabulary. These same facet/term combinations are used to catalog
information resources. Thus, through the controlled vocabulary I am
able to create relationships between resources and patrons.
The results is the display of a set of information resources designed
for individuals with particular characteristics. For example, try the
following URLs. Each points to a different patron with different
characteristics, and each page provides the ability to display the
information resources in an alphabetical or grouped view:
* Andrew Carnegie
http://dewey.library.nd.edu/morgan/portal/?cmd=patronid=194
* Leonardo D'Vinci
http://dewey.library.nd.edu/morgan/portal/?cmd=patronid=191
* Galileo Galilei
http://dewey.library.nd.edu/morgan/portal/?cmd=patronid=193
Thanks guys. I have added your names to my code.
--
Eric Morgan
dereferencing an array
How do I loop through a reference to an array?
I have the following data structure:
my %facets = (
'audiences' = [('freshman', 'senior')],
'subjects' = [('music', 'history')],
'tools' = [('dictionaries', 'catalogs')]
);
I can use this code to get the keys for %facets:
foreach my $key (sort(keys(%facets))) { print $key, \n }
But since $key points to the reference of an array, I don't know how
to loop through the referenced array.
--
Eric Lease Morgan
Head, Digital Access and Information Architecture Department
University Libraries of Notre Dame
(574) 631-8604
Re: dereferencing an array
foreach my $key1 (sort(keys(%facets))) {
foreach my $key2 (sort(keys(%facets{$key1))) {
print $key1 / $key2 \n;
}
}
Spencer
On 2/10/06, Eric Lease Morgan [EMAIL PROTECTED] wrote:
How do I loop through a reference to an array?
I have the following data structure:
my %facets = (
'audiences' = [('freshman', 'senior')],
'subjects' = [('music', 'history')],
'tools' = [('dictionaries', 'catalogs')]
);
I can use this code to get the keys for %facets:
foreach my $key (sort(keys(%facets))) { print $key, \n }
But since $key points to the reference of an array, I don't know how
to loop through the referenced array.
--
Eric Lease Morgan
Head, Digital Access and Information Architecture Department
University Libraries of Notre Dame
(574) 631-8604
--
Spencer M. Anspach, Library Systems Analyst/Programmer
Library Information Technology, Indiana University
Library E456 phone: (812) 856-5318
Bloomington, IN 47405 fax: (812) 856-4979
[EMAIL PROTECTED] pager: (812) 335-7403
Re: dereferencing an array
Ergg, just realized my copy of Programming Perl is at home. Ah well, the
old noggin is pretty sure how to do this.
Quick short answer, @{$facets{$key}}..so
foreach $foo (@{$facets{$key}}) {
print Hello, I'm $foo. Pleased to meet ya.\n;
}
or something along those lines
Jonathan T. Gorman
Visiting Research Information Specialist
University of Illinois at Champaign-Urbana
216 Main Library - MC522
1408 West Gregory Drive
Urbana, IL 61801
Phone: (217) 244-4688
On Fri, 10 Feb 2006, Eric Lease Morgan wrote:
How do I loop through a reference to an array?
I have the following data structure:
my %facets = (
'audiences' = [('freshman', 'senior')],
'subjects' = [('music', 'history')],
'tools' = [('dictionaries', 'catalogs')]
);
I can use this code to get the keys for %facets:
foreach my $key (sort(keys(%facets))) { print $key, \n }
But since $key points to the reference of an array, I don't know how to
loop through the referenced array.
--
Eric Lease Morgan
Head, Digital Access and Information Architecture Department
University Libraries of Notre Dame
(574) 631-8604
Re: dereferencing an array
On Feb 10, 2006, at 3:58 PM, Eric Lease Morgan wrote:
Now I'm going to make each value in the referenced array a
reference to a hash; I'm going to make my data structure deeper.
'More later.
Since that worked so well, I'll ask this question. Given the
following data structure, how do I print out something like this:
tools
dictionaries
websters - http://websters.com
oxford - http://oxford.edu
catalogs
und - http://catalog.nd.edu
worldcat - http://worldcat.com
my %facets = (
'tools' = [(
'dictionaries' = [(
'websters' = 'http://websters.com',
'oxford' = 'http://oxford.edu'
)],
'catalogs' = [(
'und' = 'http://catalog.nd.edu',
'worldcat' = 'http://worldcat.com'
)]
)]
);
This code doesn't cut it:
foreach my $key (sort(keys(%facets))) {
print $key, \n;
foreach my $term (@{$facets{$key}}) {
print \t, $term, \n;
}
}
Is my data structure dumb?
--
Eric Morgan
Re: dereferencing an array
On 2/10/06 Eric Lease Morgan wrote:
On Feb 10, 2006, at 3:51 PM, Jonathan Gorman wrote:
How do I loop through a reference to an array?
I have the following data structure:
my %facets = (
'audiences' = [('freshman', 'senior')],
'subjects' = [('music', 'history')],
'tools' = [('dictionaries', 'catalogs')]
);
foreach my $key (sort(keys(%facets))) { print $key, \n }
Quick short answer, @{$facets{$key}}..so
Thank you for the quick responses. Tastes great; less filling.
Now I'm going to make each value in the referenced array a reference
to a hash; I'm going to make my data structure deeper. 'More later.
Eric -- Then why use an array? Do you need to process things in a
certain non-alphbetical order, such as 'dictionaries' before 'catalogs'?
If you substitute references to hashes for the elements of your above
arrays, you'll lose the names, and only have the order to go on for
knowing what they contain.
This:
my %facets = (
'audiences' = [('freshman', 'senior')],
'subjects' = [('music', 'history')],
'tools' = [('dictionaries', 'catalogs')]
);
would become:
my %facets = (
'audiences' = [(\%freshman, \%senior)],
'subjects' = [(\%music, \%history)],
'tools' = [(\%dictionaries, \%catalogs)]
);
but then you can't use those hash names for de-referencing the interior
hashes.
Oh, you just posted another question:
Since that worked so well, I'll ask this question. Given the
following data structure, how do I print out something like this:
tools
dictionaries
websters - http://websters.com
oxford - http://oxford.edu
catalogs
und - http://catalog.nd.edu
worldcat - http://worldcat.com
c
This code doesn't cut it:
foreach my $key (sort(keys(%facets))) {
print $key, \n;
foreach my $term (@{$facets{$key}}) {
print \t, $term, \n;
}
}
This would work better (eliminate the arrays):
my %facets = (
'tools' = {
'dictionaries' = {
'websters' = 'http://websters.com',
'oxford' = 'http://oxford.edu'
},
'catalogs' = {
'und' = 'http://catalog.nd.edu',
'worldcat' = 'http://worldcat.com'
},
},
# other elements of %facets
);
# access
my $wbstr_url= $facets{tools}-{dictionaries}-{websters};
# 'http://websters.com'
my $wrldct_url = $facets{tools}-{catalogs}-{worldcat};
# 'http://worldcat.com'
# iterate -- watch out for email line-breaking
foreach my $facet_key (keys %facets) {
foreach my $sub_key (keys %{ $facets{$facet_key} } ) {
foreach my $inner_key (keys %{ $facets{$facet_key}-{$sub_key} } ) {
print $facet_key: $sub_key: $inner_key:
$facets{$facet_key}-{$sub_key}-{$inner_key} \n;
}
}
}
# prints:
tools: catalogs: worldcat: http://worldcat.com
tools: catalogs: und: http://catalog.nd.edu
tools: dictionaries: oxford: http://oxford.edu
tools: dictionaries: websters: http://websters.com
That's not so easy to read, and very redundant as far as de-referencing.
# iterate -- a little easier to keep track
foreach my $facet_key (keys %facets) {
my %sub_hash= %{ $facets{$facet_key} };
for my $sub_key (keys %sub_hash) {
my %inner_hash= %{ $sub_hash{$sub_key} };
foreach my $inner_key (keys %inner_hash) {
print $facet_key: $sub_key: $inner_key: $inner_hash{$inner_key}
\n;
}
}
}
# prints:
tools: dictionaries: oxford: http://oxford.edu
tools: dictionaries: websters: http://websters.com
tools: catalogs: worldcat: http://worldcat.com
tools: catalogs: und: http://catalog.nd.edu
Note that I didn't do any sorting in either of the above.
Programming Perl's little chapter section on data structures is
practically worthless unless you already understand nested references,
which is what it's supposed to be explaining. It just makes your head
spin. (My opinion, of course.) After years, it's easy to understand, but
I don't use it to teach from.
The main thing about multi-level data structures is to start from the
innermost elements and work outward. Build outward each level only after
you're sure you have the inner level down. If you use nested foreach()es
against the keys of your nested hashes, use different names for the keys
at each level.
If you use arrays, remember that you gain order, but you may only refer
to the elements by index, i.e., $array[0], array[1], etc.
Finally, I find that in practice I rarely need to iterate through an
entire nested structure and print or process every successive element.
Usually I already know one or more of the inner hash keys. See my
examples above labeled # access.
Taking a lesson from Extreme Programming, write the routine that is
supposed to do what you want, not a routine that just explores your data
structure. Feed your data structure to your routine, and tweak until the
correct result appears.
Data::Dummper can also be a great help in seeing how your data structure
is actually composed (although it
Re: dereferencing an array - Pt 2
My previous message got kinda long, so here's some tested Perl that does
just what Eric's last message asked for:
#!/usr/bin/perl -w
use strict;
my %facets = (
'tools' = {
'dictionaries' = {
'websters' = 'http://websters.com',
'oxford' = 'http://oxford.edu'
},
'catalogs' = {
'und' = 'http://catalog.nd.edu',
'worldcat' = 'http://worldcat.com'
},
},
# other elements of %facets
);
# iterate
foreach my $facet_key (keys %facets) {
print $facet_key\n;
my %sub_hash= %{ $facets{$facet_key} };
foreach my $sub_key (keys %sub_hash) {
print \t$sub_key\n;
my %inner_hash= %{ $sub_hash{$sub_key} };
foreach my $inner_key (keys %inner_hash) {
print \t\t$inner_key - $inner_hash{$inner_key}\n;
}
}
}
__END__
# prints:
tools
dictionaries
oxford - http://oxford.edu
websters - http://websters.com
catalogs
worldcat - http://worldcat.com
und - http://catalog.nd.edu
- Bruce
__bruce__van_allen__santa_cruz__ca__
Re: dereferencing an array - Pt 2
On Feb 10, 2006, at 5:41 PM, Bruce Van Allen wrote:
foreach my $facet_key (keys %facets) {
print $facet_key\n;
my %sub_hash= %{ $facets{$facet_key} };
foreach my $sub_key (keys %sub_hash) {
print \t$sub_key\n;
my %inner_hash= %{ $sub_hash{$sub_key} };
foreach my $inner_key (keys %inner_hash) {
print \t\t$inner_key - $inner_hash{$inner_key}\n;
}
}
}
This has been VERY helpful, and I appreciate the assistance. Now I
need to programatically build the hash.
I have this sample data structure:
my %profile = (
'subjects' = {
'astronomy' = {
'telescope world' = 'http://telescope.com',
'stars r us' = 'http://websters.com',
'asto magazine' = 'http://oxford.edu'
},
'mathematics' = {
'2 + 2 = 4' = 'http://catalog.nd.edu',
'math library' = 'http://worldcat.com'
}
},
'tools' = {
'dictionaries' = {
'websters' = 'http://websters.com',
'oxford' = 'http://oxford.edu'
},
'catalogs' = {
'und' = 'http://catalog.nd.edu',
'worldcat' = 'http://worldcat.com'
}
}
);
I use the followign code, based on the good work of Bruce, to
traverse %profile and output a set of nested HTML lists. It works for
any size of %profile. Fun!
print ul;
foreach my $facet (sort(keys(%profile))) {
print li$facet;
my %facets = %{$profile{$facet}};
print ul;
foreach my $term (sort(keys(%{$profile{$facet}}))) {
print li$term;
my %terms = %{$facets{$term}};
print ol;
foreach my $resource (sort(keys(%terms))) {
print lia href='$facets{$term}{$resource}'$resource/
a/li;
}
print /ol;
print /li;
}
print /ul;
print /li;
}
print /ul;
I now need to build %profile programatically. As I loop through a set
of information resources I can determine the following values:
1. resource name (ex: telescope world)
2. URL (ex: http://telescope.com)
3. term (ex: astronomy)
4. facet (ex: subjects)
Given these values, how can I build %profile?
--
Eric Perl Data Structures !R My Forte Morgan
