hashval and Numpy

[Uwe Schmitt]

Michael Hudson <mwh at python.net> wrote:

|>>> a = Numeric.array([1,2])
|>>> hash(a)
| 56
|>>> d = {a:1} # a will be in the 56%8-th slot (in 2.2, anyway)
|>>> a[0] = 2
|>>> hash(a)
| 57
|>>> d[a] # looks in 57%8-th slot - which is empty
| KeyError
|>>> b = Numeric.array([1,2])
|>>> hash(b)
| 56
|>>> d[b] # looks in 56%8-th slot - but what's there is not __eq__ to b!
| KeyError

| Moral: don't use mutable objects as dictionary keys.

allright,  i understand. thanks. yours, uwe.

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