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comp.lang.ruby

In Ruby, is a set just a hash without values?

Wes Gamble

3/29/2006 12:21:00 AM

A question - is there an object in Ruby analogous to a Java set, which
has hash-like functionality but no values?

Or should I just use a hash with no values?

Actually, what I'm _really_ trying to do is "unique-ize" an array based
on a particular attribute of each of it's members. My plan was to read
the unique attribute values into a hash as they come up and compare new
array member's attributes against that hash.

I bet there's a very cool way to do it ;) - if anyone knows and would
like to share, I am all ears.

Thanks,
Wes

--
Posted via http://www.ruby-....
2 Answers

Stephen Waits

3/29/2006 12:25:00 AM

0

Wes Gamble wrote:
> A question - is there an object in Ruby analogous to a Java set, which
> has hash-like functionality but no values?

require 'set' # should do what you're asking for

docs here: http://ruby-doc.org/stdlib/libdoc/set/rdoc/...

--Steve

Daniel Harple

3/29/2006 12:34:00 AM

0

On Mar 29, 2006, at 2:21 AM, Wes Gamble wrote:

> Actually, what I'm _really_ trying to do is "unique-ize" an array
> based
> on a particular attribute of each of it's members. My plan was to
> read
> the unique attribute values into a hash as they come up and compare
> new
> array member's attributes against that hash.
>
> I bet there's a very cool way to do it ;) - if anyone knows and would
> like to share, I am all ears.

Use the Set class (or SortedSet if your collection needs to be sorted
and mixes in Comparable).

$ ri Set
<snip>
The equality of each couple of elements is determined according to
Object#eql? and Object#hash, since Set uses Hash as storage.

-- Daniel