Thanks for the warning.

However in this instance the problems you noted do not occur in my case. I'm using grep to return a list of hash keys are in the superset and not the subset of two hases. However I know that the difference in the size of the two hases will only ever be one or two key/value pairs.

As I am only ever interested (for now) in the first element I wanted to return a scalar value so that later code didn't have to manage an array.

If at a later date the size of the difference does increase I will reconsider my aproach to this problem.

Cheers all.

!unlike

I write my Perl code like how I like my sex: fast and dirty. ;)