Hi all,
Ruby 1.8.5
irb(main):002:0> Set[1,2,3] ^ Set[3,4,5,5]
=> #<Set: {5, 1, 2, 4}>
Ok, looks good.
irb(main):003:0> Set[1,2,3] ^ [3,4,5,5]
=> #<Set: {1, 2, 4}>
What?! I'm confused. Do I need a refresher in Set theory or something?
Thanks,
Dan
It is the way it is implemented... subsequent 5's will toggle it on and off. You should file a bug.
···
On Nov 1, 2006, at 12:25 PM, Daniel Berger wrote:
irb(main):002:0> Set[1,2,3] ^ Set[3,4,5,5]
=> #<Set: {5, 1, 2, 4}>Ok, looks good.
irb(main):003:0> Set[1,2,3] ^ [3,4,5,5]
=> #<Set: {1, 2, 4}>What?! I'm confused. Do I need a refresher in Set theory or something?
Daniel Berger wrote:
Hi all,
Ruby 1.8.5
irb(main):002:0> Set[1,2,3] ^ Set[3,4,5,5]
=> #<Set: {5, 1, 2, 4}>Ok, looks good.
irb(main):003:0> Set[1,2,3] ^ [3,4,5,5]
=> #<Set: {1, 2, 4}>What?! I'm confused. Do I need a refresher in Set theory or something?
I think I can guess why it is happening:
irb(main):009:0> (0..10).each {|n| p Set[1,2,3] ^ ([3,4]+[5]*n)}
#<Set: {1, 2, 4}>
#<Set: {5, 1, 2, 4}>
#<Set: {1, 2, 4}>
#<Set: {5, 1, 2, 4}>
#<Set: {1, 2, 4}>
#<Set: {5, 1, 2, 4}>
#<Set: {1, 2, 4}>
#<Set: {5, 1, 2, 4}>
#<Set: {1, 2, 4}>
#<Set: {5, 1, 2, 4}>
#<Set: {1, 2, 4}>
=> 0..10
Looks like the array argument is used to flip-flop the elements of the set.
···
--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
Daniel Berger wrote:
Hi all,
Ruby 1.8.5
irb(main):002:0> Set[1,2,3] ^ Set[3,4,5,5]
=> #<Set: {5, 1, 2, 4}>Ok, looks good.
irb(main):003:0> Set[1,2,3] ^ [3,4,5,5]
=> #<Set: {1, 2, 4}>What?! I'm confused. Do I need a refresher in Set theory or something?
Are your irb entries above copied directly from the display? Or is this a
1.8.5 problem?
$ ruby -v
$ ruby 1.8.4 (2005-12-24) [i386-linux]
$irb
irb(main):002:0> require 'set'
=> true
irb(main):003:0> Set[1,2,3] ^ Set[3,4,5,5]
=> #<Set: {5, 1, 2, 4}>
irb(main):004:0> Set[1,2,3] ^ Set[3,4,5,5]
=> #<Set: {5, 1, 2, 4}>
irb(main):005:0> Set[1,2,3] ^ Set[3,4,5,5]
=> #<Set: {5, 1, 2, 4}>
···
--
Paul Lutus
http://www.arachnoid.com
Ryan Davis wrote:
···
On Nov 1, 2006, at 12:25 PM, Daniel Berger wrote:
> irb(main):002:0> Set[1,2,3] ^ Set[3,4,5,5]
> => #<Set: {5, 1, 2, 4}>
>
> Ok, looks good.
>
> irb(main):003:0> Set[1,2,3] ^ [3,4,5,5]
> => #<Set: {1, 2, 4}>
>
> What?! I'm confused. Do I need a refresher in Set theory or something?It is the way it is implemented... subsequent 5's will toggle it on
and off. You should file a bug.
Done.
Thanks for confirming my sanity.
- Dan
Daniel Berger wrote:
Ryan Davis wrote:
irb(main):002:0> Set[1,2,3] ^ Set[3,4,5,5]
=> #<Set: {5, 1, 2, 4}>Ok, looks good.
irb(main):003:0> Set[1,2,3] ^ [3,4,5,5]
=> #<Set: {1, 2, 4}>What?! I'm confused. Do I need a refresher in Set theory or something?
It is the way it is implemented... subsequent 5's will toggle it on
and off. You should file a bug.Done.
Thanks for confirming my sanity.
In what way is this a bug? I'm not aware of set theory saying anything about the intersection of a set with an array.
···
On Nov 1, 2006, at 12:25 PM, Daniel Berger wrote:
Jeffrey Schwab wrote:
Daniel Berger wrote:
Ryan Davis wrote:
irb(main):002:0> Set[1,2,3] ^ Set[3,4,5,5]
=> #<Set: {5, 1, 2, 4}>Ok, looks good.
irb(main):003:0> Set[1,2,3] ^ [3,4,5,5]
=> #<Set: {1, 2, 4}>What?! I'm confused. Do I need a refresher in Set theory or something?
It is the way it is implemented... subsequent 5's will toggle it on
and off. You should file a bug.Done.
Thanks for confirming my sanity.
In what way is this a bug? I'm not aware of set theory saying anything about the intersection of a set with an array.
Arrays already behave like sets in some ways. They have set-like operators:
irb(main):009:0* [1,2,3] & [2,3,4]
=> [2, 3]
irb(main):010:0> [1,2,3] | [2,3,4]
=> [1, 2, 3, 4]
irb(main):011:0> [1,2,3] - [2,3,4]
=> [1]
But this argument falls down because arrays don't have symmetric difference:
irb(main):012:0> [1,2,3] ^ [2,3,4]
NoMethodError: undefined method `^' for [1, 2, 3]:Array
from (irb):11
···
On Nov 1, 2006, at 12:25 PM, Daniel Berger wrote:
--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407