Using __repr__ or __str__ for own printable class?
aleax at aleax.it
Sat Apr 12 17:11:44 CEST 2003
Steven Taschuk wrote:
> Pickle doesn't use __repr__; it has other, more reliable, ways of
> getting object state.
> __repr__ is used by: (1) '%r' % foo and repr(foo); (2) '%s' % foo,
> str(foo), and print foo if __str__ isn't provided; and (3) the
> interactive interpreter, when printing the value of an expression
> entered at the prompt. (And no doubt, other places that I've
IMHO the most maddening use of __repr__ is that done by the
implementation of __str__ for all built-in container types:
>>> class X:
... def __str__(self): return 'str'
... def __repr__(self): return 'rep'
>>> print [X()]
There's supposed to be a good reason for this to print [rep],
rather than [str] as common sense would suggest, but I keep
forgetting it (so it's probably nor very compelling;-).
More information about the Python-list