On 1/15/2010 6:10 PM, Sean DiZazzo wrote:
On Jan 15, 2:22 pm, Terry Reedy<tjre...@udel.edu> wrote:
On 1/15/2010 3:37 PM, Sean DiZazzo wrote:
Should the following be legal?
class TEST(object): pass
...
t = TEST()
setattr(t, "", "123")
getattr(t, "")
'123'
Different people have different opinions as to whether setattr (and
correspondingly getattr) should be strict or permissive as to whether or
not the 'name' string is a legal name. CPython is permissive. The
rationale is that checking would take time and prevent possible
legitimate use cases.
CPython is actually looser than this. Try
t.__dict__[1] = 2
Now there is an 'attribute' whose 'name' is an int! -- and which can
only be accessed via the same trick of delving into the internals. This
is, however, implementation behavior that would go away if an
implementation used string-key-only dicts to store attributes.
Terry Jan Reedy
Interesting. I can understand the "would take time" argument, but I
don't see any legitimate use case for an attribute only accessible via
getattr(). Well, at least not a pythonic use case.
That was my first thought, but one thing I thought of would be a proxy
object for remote objects coded in a language with different name rules,
or any situation where 'names' and values come over the wire to be
stored and later retrieved, so that all 'foreign' attribute access was
done with set/get/del/attr.
I expect that creative Python programmers have found other uses too.
Terry Jan Reedy
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