in reply to Perl Best Practices for naming variables
I also have no strong preferences on giving singular or plural names to arrays. Sometimes one looks right, sometimes the other.
I do have a strong preference that hashes get singular names, though.
The single most useful comment that I've seen on using hashes is, Think of a hash lookup as "of". That is, $age{'Sam'} should be read "age of Sam". Or, if you need it to be really unambiguous, $age_by_name{'Sam'} can be read "Age of whoever is named Sam."
This little recommendation fits every idiomatic use of hashes that readily comes to mind. When I was just starting Perl, it made it easy for me to spot where and when a hash would be useful, and decide what it should be called. With the benefit of experience I know of no better way to figure that out.
However that little linguistic principle that I treasure is ruined if you give hashes singularplural names. (Unless the values are array refs, in which case I would give it a plural name without even pausing to think about it.)
Update: Changed singular to plural per private note from hv.