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Re: When do I need to override hash?
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Re: When do I need to override hash?


  • Subject: Re: When do I need to override hash?
  • From: Kyle Sluder <email@hidden>
  • Date: Thu, 20 Aug 2009 13:37:25 -0700

On Thu, Aug 20, 2009 at 1:33 PM, Clark Cox<email@hidden> wrote:
> -isEqual: is how Cocoa collections define equality. Saying that two
> objects are "equal" means, by definition, that -[obj1 isEqual: obj2]
> returns true.

This has nothing to do with -hash.

P: Two objects are equal.
Q: They have the same hash.

P -> Q.

Note that Q does not imply P.

--Kyle Sluder
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  • Follow-Ups:
    • Re: When do I need to override hash?
      • From: Clark Cox <email@hidden>
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      • From: Shawn Erickson <email@hidden>
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References: 
 >When do I need to override hash? (From: Gideon King <email@hidden>)
 >Re: When do I need to override hash? (From: Nathan Vander Wilt <email@hidden>)
 >Re: When do I need to override hash? (From: Gideon King <email@hidden>)
 >Re: When do I need to override hash? (From: "Adam R. Maxwell" <email@hidden>)
 >Re: When do I need to override hash? (From: Seth Willits <email@hidden>)
 >Re: When do I need to override hash? (From: David Duncan <email@hidden>)
 >Re: When do I need to override hash? (From: Clark Cox <email@hidden>)
 >Re: When do I need to override hash? (From: Bryan Henry <email@hidden>)
 >Re: When do I need to override hash? (From: Clark Cox <email@hidden>)

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