Python: Hash value of wx.DateTime

• dalton_tom / 116 / Fri, 27 Mar 2009 04:58:00 GMT / Comments (0)
• Hi,
  
  I've been using wxPython at work as part of rewriting a lot of our user interface and just wanted to say firstly; thanks to all the developers! It's a really nice package, especially since a lot of our legacy code uses wxWidgets.
  
  However, I recently ran into what I think might be a problem. While doing some work with DateTimes, I found that wx.DateTime objects representing the same date and time hash to different values. Specifically, they hash to their id. So if you have:
  
  date1 = wx.DateTime().Set(01,01,2007,12,00,00,00)
  date2 = wx.DateTime().Set(01,01,2007,12,00,00,00)
  
  then;
  
  date1 == date2
  True
  
  but
  
  date_set = set(date1)
  date2 in date_set
  False
  
  This is not what I'd expect, as the Python documentation (v2.4.3) says that if you're making your own objects, then the __hash__() method of two equal objects should return the same value for both. Since date1 is equal (as far as I can tell) to date2, I expected it to hash to the same value and thus work as expected in set membership. Is this a bug, or is this intended behaviour? If it's intended behaviour, then can you explain to me why it's this way? If it is intended, then it's no problem as I can always make my own DateTime subclass that just overrides the __hash__() function, but my main concern was that I may have found a bug.
  
  Thanks for your time :-)
  
  Tom Dalton
• Keywords:

  hash, value, wx.datetime, python

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