note
tilly
First of all, Perl is list-oriented and handles passed in
arguments by reference. Therefore the Perlish way to do
this is to just take a list of numbers and work with that.
But I will play off the rule as given even though it is
not the API I would choose.<P>
Also the stricture to avoid having any variables should
not be looked at as just a bizarre restriction. People who
program in a functional style often do that voluntarily.
With that in mind I offer the following version that
follows the restrictions as a matter of intentional style
and <i>just happens</i> to solve a more complex problem.
The function is avg_nested which extracts the numbers
from a nested set of arrays of arrays and computes the
average of the entire list:
<code>
sub avg {
sum(@_) / @_;
}
sub avg_nested {
avg(flatten_arrays(@_));
}
sub flatten_arrays {
map {ref($_) ? flatten_arrays(@$_) : $_} @_;
}
sub sum {
@_ ? shift(@_) + sum(@_) : 0;
}
</code>
<P>
<B>UPDATE</B><BR>
[jynx] caught me. I wrote it, then changed a function
name at the last minute and didn't test properly. I
forgot to change one flatten to flatten_arrays...
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