# TheYAML change the id of Object **URL:** \ **Category:** Ruby\ **Created:** [December 19, 2005, 3:09pm UTC](https://www.ruby-forum.com/t/theyaml-change-the-id-of-object/50643 "2005-12-19T15:09:49Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![andrea](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c37758/32.png) [@andrea](https://www.ruby-forum.com/u/andrea)\ **Post date:** [December 19, 2005, 3:09pm UTC](https://www.ruby-forum.com/t/theyaml-change-the-id-of-object/50643/1 "2005-12-19T15:09:49Z")
I’m using an hash object and i use a Termine Object for the key and, for now, a String for the value. The class Termine is this: class Termine DEFAULT\_LANG = “it” attr\_accessor :descrizione attr\_accessor :lingua def initialize(descrizione="", lingua=DEFAULT\_LANG) @descrizione = descrizione @lingua = lingua end end In my test file all is good (compare, edit, delete and reference), but if I dump all in a file YAML and then I load the file YAML the equal assertion have a failure. The attributes ‘descrizione’ and ‘lingua’ on the key are the same, but the problem is that the id of the object is changed… and so there is the failure. test\_yaml: before hash dump #Termine:0x2ada6a8:Key T4 in lingua it – Value: Definizione uno #Termine:0x2ada720:Key T3 in lingua it – Value: Definizione tre #Termine:0x2ada750:Key T2 in lingua it – Value: Definizione due #Termine:0x2ada780:Key T1 in lingua it – Value: Definizione uno test\_yaml: after dump (is clear) test\_yaml: after load #Termine:0x2ad6400:Key T4 in lingua it – Value: Definizione uno #Termine:0x2ad5f20:Key T3 in lingua it – Value: Definizione tre #Termine:0x2ad5a40:Key T2 in lingua it – Value: Definizione due #Termine:0x2ad5518:Key T1 in lingua it – Value: Definizione uno How can I solve this problem? Thanks to all for the help… –Andrea. ---
**Author:** ![andrea](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c37758/32.png) [@andrea](https://www.ruby-forum.com/u/andrea)\ **Post date:** [December 19, 2005, 4:23pm UTC](https://www.ruby-forum.com/t/theyaml-change-the-id-of-object/50643/2 "2005-12-19T16:23:47Z")
On Dec 19, 2005, at 9:10 AM, Andrea wrote: > ``` > @descrizione = descrizione > > ``` > > #Termine:0x2ad5f20:Key T3 in lingua it – Value: Definizione tre You need to overload the == operator and the hash method. class Termine alias eql? == def ==(other) descrizione == other.descrizione and lingua == other. lingua end def hash (descrizione + lingua).hash end end t = Termine.new(“Hi”) t2 = Termine.new(“Hi”) t == t2 #=\> true h = {} h[t] = “short hello” h #=\> {#\=\>“short hello”} h.has\_key?(t2) #=\> true ---
**Author:** ![andrea](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c37758/32.png) [@andrea](https://www.ruby-forum.com/u/andrea)\ **Post date:** [December 19, 2005, 4:36pm UTC](https://www.ruby-forum.com/t/theyaml-change-the-id-of-object/50643/3 "2005-12-19T16:36:41Z")
Logan C. wrote: > On Dec 19, 2005, at 9:10 AM, Andrea wrote: > > > ``` > > @descrizione = descrizione > > > > ``` > > > > #Termine:0x2ad5f20:Key T3 in lingua it – Value: Definizione tre > > You need to overload the == operator and the hash method. > > class Termine > alias eql? == > def ==(other) > descrizione == other.descrizione and lingua == other. lingua > end > def hash > (descrizione + lingua).hash > end > end > > t = Termine.new(“Hi”) > t2 = Termine.new(“Hi”) > > t == t2 #=\> true > > h = {} > h[t] = “short hello” > h #=\> {#\=\>“short > hello”} > h.has\_key?(t2) #=\> true Thank for your help… this is that I need… –Andrea ---
**Author:** ![andrea](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c37758/32.png) [@andrea](https://www.ruby-forum.com/u/andrea)\ **Post date:** [December 19, 2005, 4:59pm UTC](https://www.ruby-forum.com/t/theyaml-change-the-id-of-object/50643/4 "2005-12-19T16:59:55Z")
> > > > > “R” == Ross B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes: R\> def ==(o) An hash use #hash and #eql?, not #== Guy Decoux ---
**Author:** ![andrea](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c37758/32.png) [@andrea](https://www.ruby-forum.com/u/andrea)\ **Post date:** [December 19, 2005, 5:05pm UTC](https://www.ruby-forum.com/t/theyaml-change-the-id-of-object/50643/5 "2005-12-19T17:05:56Z")
On Dec 19, 2005, at 10:47 AM, Ross B. wrote: > > ``` > > end > > > > ``` > > > > hello"} > > end > h[d = Dclz.new] = “Expected” > > (Tried on both ruby 1.8.3 (2005-09-21) [i386-linux] and ruby 1.9.0 > (2005-12-16) [i686-linux]) > > – > Ross B. - removed\_email\_address@domain.invalid As ts already mentioned, you missed the eql? part. Me aliasing it to == and implementing == instead is a function of my C++ (as opposed to lisp or smalltalk(?) ) upbringing. ---
**Author:** ![andrea](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c37758/32.png) [@andrea](https://www.ruby-forum.com/u/andrea)\ **Post date:** [December 19, 2005, 4:50pm UTC](https://www.ruby-forum.com/t/theyaml-change-the-id-of-object/50643/6 "2005-12-19T16:50:54Z")
On Mon, 19 Dec 2005 15:21:22 -0000, Logan C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > ``` > alias eql? == > > ``` > > t == t2 #=\> true > > h = {} > h[t] = “short hello” > h #=\> {#\=\>“short > hello”} > h.has\_key?(t2) #=\> true I was playing around with this, and now I’m doubly worried I have a bug, or have missed something else. The last line in your code gives out ‘false’ for me. I was experimenting with this: class Dclz @str = “A string” attr\_reader :str def ==(o) self.str == o.str end def ===(o) self.str === o.str end def hash self.str.hash end end case Dclz.new when Dclz.new puts “Works” else puts “doesn’t” end # =\> “Works” h = Hash.new { “Failure” } h[d = Dclz.new] = “Expected” puts Dclz.new == Dclz.new # =\> true puts Dclz.new.hash == Dclz.new.hash # =\> true puts h[d] # =\> “Expected” puts h[Dclz.new] # =\> “Failure” huh!!! And I cannot understand what’s happening here. Someone, please confirm that I’m either sane or stupid? (Tried on both ruby 1.8.3 (2005-09-21) [i386-linux] and ruby 1.9.0 (2005-12-16) [i686-linux]) ---
**Author:** ![andrea](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c37758/32.png) [@andrea](https://www.ruby-forum.com/u/andrea)\ **Post date:** [December 19, 2005, 5:23pm UTC](https://www.ruby-forum.com/t/theyaml-change-the-id-of-object/50643/7 "2005-12-19T17:23:57Z")
On Mon, 19 Dec 2005 16:04:56 -0000, Logan C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > As ts already mentioned, you missed the eql? part. Me aliasing it to == > and implementing == instead is a function of my C++ (as opposed to lisp > or smalltalk(?) ) upbringing. Yes, I see. If I move your alias to after the definition, or just implement eql?, it works. I assumed you were saving a reference to the original == as ‘eql?’ (missed that it already existed), which is why I got ‘false’ first time around. It was just that having my suspicion apparently confirmed kind of made me worried 😉 Cheers 🙂 ---
**Author:** ![andrea](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c37758/32.png) [@andrea](https://www.ruby-forum.com/u/andrea)\ **Post date:** [December 19, 2005, 5:14pm UTC](https://www.ruby-forum.com/t/theyaml-change-the-id-of-object/50643/8 "2005-12-19T17:14:57Z")
On Mon, 19 Dec 2005 15:56:51 -0000, ts [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > > > > “R” == Ross B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes: > > R\> def ==(o) > > An hash use #hash and #eql?, not #== Ahh, there it goes 🙂 Thanks kindly.