Mapping to an associative hash

THRAK has asked for the wisdom of the Perl Monks concerning the following question:

I have a tab delimited file that is a DB export of an addressbook. I want to map the data from this file into a hash that has associative keys. I can read the data into an array with no problem, but is there an easy way to map this into the hash? Or is there a way to split things into the hash instead of an array? I believe going from the array to a hash isn't too difficult, but I need to get to an associative hash. Maybe array -> hash -> associative hash? Don't know, that's why I'm posting this!

/usr/bin/perl -w

use strict;

my $import_file = shift || 'addresses';
my @tmp;
my %import_data =(
                        'id'                        => '',
                        'username'                => '',
                        'domain'                    => '',
                        'address'                => '',
                        'firstname'                => '',
                        'lastname'                => '',
                        'nickname'                => '',
                        'type'                    => '',
                        'street'                    => '',
                        'city'                    => '',
                        'state'                    => '',
                        'zip'                        => '',
                        'country'                => '',
                        'company'                => '',
                        'home_phone'            => '',
                        'work_phone'            => '',
                        'pager'                    => '',
                        'cellular'                => '',
                        'fax'                        => '',
                        'other'                    => '',
                        'birth_month'            => '',
                        'birth_day'                => '',
                        'birth_year'            => '',
                        'birthday'                => 'undef',
                        'title'                    => '',
                        'status'                    => '',
                        'time_stamp'            => '',
                        'middleinitial'        => '',
                        'nameprefix'            => 'undef',
                        'namesuffix'            => 'undef',
                        'street2'                => '',
                        'website'                => '',
                        'notes'                    => '',
                        'department'            => 'undef',
                        'assistant'                => 'undef',
                        'dstreet'                => '',
                        'dstreet2'                => '',
                        'dcity'                    => '',
                        'dstate'                    => '',
                        'dzip'                    => '',
                        'dcountry'                => '',
                        'dphone1'                => 'undef',
                        'dphone2'                => 'undef',
                        'daddress'                => '',
                        'dspouse'                => 'undef',
                        'danniversary_day'    => '',
                        'danniversary_month'    => '',
                        'dnotes'                    => 'undef',
                        'dwebsite'                => '',
                        'daddress2'                => '',
                        'danniversary_year'    => '',
                        'category'                => '',
                        'prime_phone'            => '',
                      );



open(FILE, "< $import_file") or die "Cannot open $import_file ERR: $!\
+n";
while (<FILE>) {
    @tmp = split /\t/;
    #map @tmp to %import_data here
    #then call a sub-routine to manipulate
}
close FILE;
[download]

Thank You,

-THRAK
www.polarlava.com
_{janitored by ybiC: <readmore> tags around long codeblock, as per Monastery convention}

Comment on Mapping to an associative hash Download Code

Replies are listed 'Best First'.
Re: Mapping to an associative hash by Thelonius (Priest) on Sep 16, 2003 at 21:06 UTC
Sure thing! If you have the keys you want in an array @keys (in the order that the data appears in the file), then all you need to say is: `while (<FILE>) { my %data; chomp; @data{@keys} = split /\t/; # then call subroutine }` [download]	[reply] [d/l]
Re: Mapping to an associative hash by Zaxo (Archbishop) on Sep 16, 2003 at 21:21 UTC
You can use your knowlege of the keys/column names to make the file an array of hashes or, if there can be constructed a 'primary key' from the data, a hash of hashes. Assuming that the 'id' is unique, it might serve. In any case, make a constant array of your column names and fill in a hash slice over that with the data. Here is yet another way, making a hash of hashes on id, with the second level hashes constructed directly from a list, `my @keys = qw( id username domain address); # and so on my %addressbook; while (<>) { # or whatever handle my @data = split /\t/; $addressbook{$data[0]} = { map { ($keys[$_] => $data[$_]) } 1..$#keys }; }` [download] There are lots of ways to do this. After Compline, Zaxo	[reply] [d/l]
Re: Mapping to an associative hash by shenme (Priest) on Sep 16, 2003 at 21:20 UTC
Your records have tab-delimited fields, so "`@tmp = split /\t/;`" copies those fields, in order, into the array. Are the fields named in the same order you show in `%import_data`, that is, is the 'id' value first, then the 'username' value, and so on? You just need to stuff name/value pairs into your hash using names in the same order as your values. `my @field_names = qw( id username domain .... prime_phones ); my @field_values = split /\t/; @input_data{@field_names} = @field_values;` [download] That's using a "hash slice". A longer parallel version (untested) `my @field_names = qw( id username domain .... prime_phones ); my @field_values = split /\t/; for( my $i=0; $i<@field_values; ++$i ) { $input_data{$field_names[$i]} = $field_values[$i]; }` [download]	[reply] [d/l] [select]
Re: Re: Mapping to an associative hash by THRAK (Monk) on Sep 17, 2003 at 13:04 UTC
shenme, I'm going with your first suggestion. Quick, easy and simple. Thanks. -THRAK www.polarlava.com	[reply]
Re: Mapping to an associative hash by IOrdy (Friar) on Sep 17, 2003 at 01:56 UTC
You could use DBD::CSV and supply the column names when you create the db handle. Then just $sth->fetchrow_hashref like you would any other sql query result. update: added some code :) `my $dbh = DBI->connect(q{DBI:CSV:}); $dbh->{'csv_tables'}->{'mytable'} = { 'file' => 'mytable.csv', 'sep_char' => "\t" 'col_names' => ["col_a", "col_b", "col_c"] }; my $sth = $dbh->prepare("SELECT m.col_a, m.col_c FROM mytable m"); $sth->execute; my @rows; while (my $row = $sth->fetchrow_hashref) { push @rows, $row; }` [download]	[reply] [d/l]
Re: Mapping to an associative hash by CountZero (Bishop) on Sep 17, 2003 at 06:02 UTC
IOrdy's comment made me think of the following: if the data is an export of a database, can't you directly access the database through some of the DBI::DBD combo's? CountZero "If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law	[reply]
Re: Re: Mapping to an associative hash by THRAK (Monk) on Sep 17, 2003 at 13:01 UTC
Your logic is correct, but this is part of a migration project and I don't have access to the database from which the data is coming. This is being supplied by a third-party as tab delimited files. -THRAK www.polarlava.com	[reply]
Re: Mapping to an associative hash by CountZero (Bishop) on Sep 16, 2003 at 21:25 UTC
Is perhaps a "hash of hashes" what you are looking for? I.e. you have a top-level hash which is keyed by the ID-number and which refers to another hash which has all the keys you mention. If that fits your idea, have a look at `perldoc perldsc` which will explain it in full detail. CountZero "If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law	[reply] [d/l]
Re: Mapping to an associative hash by dragonchild (Archbishop) on Sep 16, 2003 at 21:10 UTC
hashes are also known as associative ararys. hashing, by its nature, is associative. So, "associative hash" is redundant. ------ We are the carpenters and bricklayers of the Information Age. The idea is a little like C++ templates, except not quite so brain-meltingly complicated. -- TheDamian, Exegesis 6 Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.	[reply]


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