Perl's hashes (formerly known as associative arrays) can be compared to database tables, where the key of each hash member equates to the primary key of each row of the table, and the value in the has equates to the other field(s) in the record. For Perl trainees with a background in programming in some of the more mature programming languages such as C and Fortran, this comparison isn't effective, so on our courses we start by saying "wouldn't it be nice if you could have and array [list] where you didn't have to number the elements, but could name them?". For such trainees, the practical at the end of the module requires a great deal of concentration, but almost inevitably it end up with the trainee understanding not only the mechanism of hashes, but also some techniques for making best use of them.

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Associated topic - Perl - FTP and Telnet Modules

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