Path: utzoo!attcan!uunet!decwrl!elroy.jpl.nasa.gov!jpl-devvax!lwall
From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: #elements in assoc array / array in scalar context
Message-ID: <8925@jpl-devvax.JPL.NASA.GOV>
Date: 30 Jul 90 18:24:01 GMT
References: <15429@thorin.cs.unc.edu>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 19

In article <15429@thorin.cs.unc.edu> tell@oscar.cs.unc.edu () writes:
: 
: What is the recommended way to find out how many elements are in an
: associative array?  I don't see any method that looks particularly
: efficient.

There isn't any efficient way.  You can find out how many buckets in the
hash table are in use, which will give you an approximation for non-dbm
files, since most filled buckets will only have a single entry.  I suppose
I could keep a count, but I don't.  And such a count wouldn't work on dbm
files anyway.  Currently, in a scalar context, %array returns the
filled_buckets/allocated_buckets ratio.  That's 0/4 on an empty associative
array.  After the next patch, it will return 0 if no buckets are filled,
so you can at least use %array as a boolean.

Given the problem with dbm files, I don't anticipate changing Perl to
keep track.  If you want the count, then $count++.

Larry