[#385051] How to order Structs based on two fields — Iñaki Baz Castillo <ibc@...>

Hi, I've a struct like this:

20 messages 2011/07/01
[#385052] Re: How to order Structs based on two fields — Iñaki Baz Castillo <ibc@...> 2011/07/01

2011/7/1 Iñaki Baz Castillo <ibc@aliax.net>:

[#385057] Re: How to order Structs based on two fields — Robert Klemme <shortcutter@...> 2011/07/01

On Fri, Jul 1, 2011 at 12:55 PM, Iki Baz Castillo <ibc@aliax.net> wrote:

[#385069] Offering Help — Joe Peric <peric.joe@...>

I'm new to Ruby and I am willing to learn. Anyone need help on a

18 messages 2011/07/01
[#385072] Re: Offering Help — Jeremy Heiler <jeremyheiler@...> 2011/07/01

On Fri, Jul 1, 2011 at 11:43 AM, Joe Peric <peric.joe@gmail.com> wrote:

[#385073] Re: Offering Help — Joe Peric <peric.joe@...> 2011/07/01

Never heard of it, but I'll get right on it. Thanks.

[#385082] Re: Offering Help — Joe Peric <peric.joe@...> 2011/07/02

Just finished this. I had to find some more info on exceptions to get

[#385083] Re: Offering Help — Jeremy Heiler <jeremyheiler@...> 2011/07/02

On Sat, Jul 2, 2011 at 1:39 PM, Joe Peric <peric.joe@gmail.com> wrote:

[#385102] symbol vs string for hash keys — Intransition <transfire@...>

What are the important factors to consider when deciding whether to

12 messages 2011/07/03

[#385160] Fatal Error with Ruby/GTK2, Homebrew, Green Shoes, and OSX Snow Leopard — Timothy Barnes <barnes7td@...>

I posted the below question to the Shoes mailing list and got back the

10 messages 2011/07/09

[#385194] RubyInstaller Extras — Jon <jon.forums@...>

Since 2009, we've been pleased to include Huw Collingbourne's The Book of Ruby with RubyInstaller. Well now, Huw has a newly updated version, and he's published it with No Starch Press.

11 messages 2011/07/12

[#385207] Creating a range of directories — Simon Harrison <simon@...>

I'm wanting to create a range of directories with a prefix, like the

13 messages 2011/07/13

[#385276] Is there a more efficient way to remove data from a string? — Eddie Catflap <catflaporama@...>

Hi

9 messages 2011/07/15

[#385297] Help needed for a new release of text-hyphen — Austin Ziegler <halostatue@...>

I've had folks asking me for a release of text-hyphen that works with

12 messages 2011/07/15

[#385326] Comparing hashes based on their keys — Stefano Mioli <stefano.mioli@...>

Hi list,

13 messages 2011/07/15

[#385342] moving a 1.8.6 install? — Roggie Boone <rogboone@...>

Is it possible to move the gems from a Ruby 1.8.6 install on an (old)

10 messages 2011/07/15

[#385410] Better name for #zip_with — Intransition <transfire@...>

Any ideas for a better name for:

13 messages 2011/07/18

[#385452] Ruby + USB + CCTV Camera Driver? — "Bob Carpenter." <rgc3679@...>

I want to write a Ruby driver that handles the feed from A CCTV camera.

23 messages 2011/07/18
[#385459] Re: Ruby + USB + CCTV Camera Driver? — William Rutiser <wruyahoo05@...> 2011/07/18

On 2011-07-18 1:00 PM, Bob Carpenter. wrote:

[#385461] Re: Ruby + USB + CCTV Camera Driver? — "Bob Carpenter." <rgc3679@...> 2011/07/18

William Rutiser wrote in post #1011466:

[#385462] Re: Ruby + USB + CCTV Camera Driver? — Hassan Schroeder <hassan.schroeder@...> 2011/07/18

On Mon, Jul 18, 2011 at 11:51 AM, Bob Carpenter. <rgc3679@yahoo.com> wrote:

[#385464] Re: Ruby + USB + CCTV Camera Driver? — "Bob Carpenter." <rgc3679@...> 2011/07/18

Hassan Schroeder wrote in post #1011472:

[#385471] Re: Ruby + USB + CCTV Camera Driver? — Hassan Schroeder <hassan.schroeder@...> 2011/07/18

On Mon, Jul 18, 2011 at 12:58 PM, Bob Carpenter. <rgc3679@yahoo.com> wrote:

[#385474] Re: Ruby + USB + CCTV Camera Driver? — Phillip Gawlowski <cmdjackryan@...> 2011/07/18

On Tue, Jul 19, 2011 at 12:18 AM, Hassan Schroeder

[#385477] Re: Ruby + USB + CCTV Camera Driver? — "Bob Carpenter." <rgc3679@...> 2011/07/19

Phillip Gawlowski wrote in post #1011503:

[#385509] A beginner question. — "Cajus A." <cajus_@...>

Hi i'm trying to write and example program where you speak to a

12 messages 2011/07/19

[#385542] Splitting strings — Ryan Mckenzie <ryan@...>

Hi all,

18 messages 2011/07/19

[#385565] error building ruby p290 — Dev Guy <devguy.ca@...>

I get the following build error on my Linux box while trying to build

12 messages 2011/07/20

[#385629] Are Job Ads OK? — Lee Hughes <lee@...>

Is it OK to post Ruby job ads on this forum?

12 messages 2011/07/21

[#385847] String manuplation example — kotin 76 <kotin76@...>

Hi,

15 messages 2011/07/27

[#385860] Counting lines of code in a ruby code file ignoring method code lines in the process — Harry Truax <htruax@...>

Hello,

8 messages 2011/07/27

[#385936] Help in Pointer — Tridib Bandopadhyay <tridib04@...>

Hello

18 messages 2011/07/29

[#386012] Ruby a "4th generation language"? Credible sources? — Albert Schlef <albertschlef@...>

I've noticed that Wikipedia says that "C#, Java" are 3'rd generation

13 messages 2011/07/31

[#386050] system stack error in ObjectSpace.each_object — luke gruber <luke.gru@...>

Hey guys, I'm just starting to mess around with metaprogramming in Ruby,

14 messages 2011/07/31
[#386052] Re: system stack error in ObjectSpace.each_object — Josh Cheek <josh.cheek@...> 2011/07/31

On Sun, Jul 31, 2011 at 4:29 PM, luke gruber <luke.gru@gmail.com> wrote:

[#386055] Re: system stack error in ObjectSpace.each_object — luke gruber <luke.gru@...> 2011/08/01

> Typically, SystemStackError is due to recursing for too long, perhaps I

[#386058] Re: system stack error in ObjectSpace.each_object — Robert Klemme <shortcutter@...> 2011/08/01

On Mon, Aug 1, 2011 at 3:56 AM, luke gruber <luke.gru@gmail.com> wrote:

Re: Comparing hashes based on their keys

From: Stefano Mioli <stefano.mioli@...>
Date: 2011-07-15 18:32:24 UTC
List: ruby-talk #385335
On 7/15/11 6:04 PM, Robert Klemme wrote:

>> Two hashes, let's call them h1 and h2, are to be considered equal if:
>>
>> * they have the same keys
>>
>> * h1[:x] and h2[:x] are both hashes, and they are equal according to the
>> very same rules you are reading ;)
>>
>> * they are both nil
>
> It seems your spec is not very precise because your bullet list mixes
> AND and OR.  I assume you meant
>
> Two objects o1 and o2 are considered equal for this relation if and only if
>
> ( o1 is nil AND o2 is nil ) OR
> ( o1 is a Hash AND o2 is a Hash AND
>    o1.keys == o2.keys AND
>    for each key k ( o1[k] is not a Hash OR
>                            o2[k] is not a Hash OR
>                            o1[k] equals o2[k] according to this relation ) )

Exactly.
Sorry about the confusion.

>> def compare(hash1, hash2)
>
> I would rename arguments because these need not be Hashes.

Fair enough.

>>   args = [hash1, hash2]
>>
>>   return true if args.all? {|h| h.nil?}
>>   return false if args.one? {|h| h.nil?}
>>
>>   hash1.each_key do |k|
>>     values = [hash1[k], hash2[k]]
>>
>>     if values.all? {|h| h.is_a?(Hash)}
>>       return compare(*values)
>>     else
>>       return false if values.one? {|value| value.nil? }
>>     end
>>   end
>>
>>   true
>> end
>
> Hm, I'd probably remove #all?, #any? and the like and code conditions
> directly - especially since you are always dealing with two items
> because it's likely faster.  Your code creates a lot of temporary
> Arrays along the way.

True.
On the other hand, the hashes will be fairly small, so performance 
wasn't the main goal.

That, and I the fact that I find:

	[x, y].all? {|x| x.is_a?(Hash) }

to be a bit more nice-looking than

	if x.is_a?(Hash) && y.is_a?(Hash)

But you make a very good point, thanks.

> Btw, I believe your implementation misses the case where hash2's key
> set is a superset of hash1's, i.e. contains additional keys.

True. I posted again the link to the gist with a revised version 
according to Rob's suggestions.


Thank you very much, Robert.
Ah, there are so many things to learn.

-- 
Stefano Mioli

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