[FWP] Range spec to list/hash

[Prakash Kailasa <PrakashK@bigfoot.com>]

Several times in the recent past I have had to include or exclude
things from a list such as records in a file, messages in a mailbox
etc. These lists are indexed by numbers starting with 1.

The include/exclude spec is a comma separated numbers/range of numbers,
An example: the spec 2,17,35-37,49,61-63 expands to the list of numbers
(2, 17, 35, 36, 37, 49, 61, 62, 63).

I came up with the following ($range is expanded into @list):

@list = map {m/(\d+)\-(\d+)/ ?  ($1..$2) : $_;} split ",", $range;

On occasion I wanted it to exapnd it to a hash with the numbers as keys,
and a true value such as 1 being the value. I augmented the above to:

%hash = map {$_ => 1} map {m/(\d+)\-(\d+)/ ?  ($1..$2) : $_;} split ",",
$range;

I am sure that the gurus on this list can offer better solutions.

/prakash

==== Want to unsubscribe from Fun With Perl?  Well, if you insist...
==== Send email to <fwp-request@technofile.org> with message _body_
====   unsubscribe