... but not sure how to make (hash?) to just type smith and get both emails.

Two points here: 1) partial match and 2) multiple values to one key

1. For perl hashes, the only way to get matching keys of a hash for a given string, is performing a pattern match on the entire set of keys. 

my @matching_keys = grep /$customer/, keys %Customer;

[download]

There are other hash implementations close to the perl core which live in extensions. For instance, there is DB_File which interfaces to Berkeley DB and provides binary trees. This implementation has partial match built in.

2. A perl hash consists of key/value pairs. If you want to store more than one item in the value slot, you have to store the reference to a container - a reference to an anonymous array or hash, which you later dereference. 

    # $Customer{$customer} = $_;
    push @{$Customer{$customer}}, $_; # use value slot as anonymous ar
+ray

# later

          # print "Customer: $Customer{$customer}\n";
          print join("\n", "Customer:", @{$Customer{$customer}}), "\n"
+;

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Again, the DB_File module is an alternative here. Its BTREE file type optionally allows a single key to be associated with an arbitrary number of values. File isn't necessarily a external file, since Berkeley DB allows the creation of in-memory databases.

See grep, push, join and DB_File.

perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'

In reply to Re: The Art of Hashing by shmem
in thread The Art of Hashing by Anonymous Monk

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