Rolf Wester wrote:
Hi,I would like to define methods using exec like this: class A: def __init__(self): cmd = "def sqr(self, x):\n return x**2\nself.sqr = sqr\n" exec cmd a = A() print a.sqr(a, 2) This works, but I have to call sqr with a.sqr(a, 2), a.sqr(2) does not work (TypeError: sqr() takes exactly 2 arguments (1 given)). Is there a possibility to define methods using exec and getting normal behavior? I would be very appreciative for any help. With kind regards Rolf Wester
I'll try to ignore you are using the exec statement which is an error :o) a.sqr(2) would have worked only if sqr was a *bound* method. print a.sqr <function sqr at 0x94ecd14> to oppose to print a.__init__ <bound method A.__init__ of <__main__.A instance at 0x948734c>> You cannot dynamically bind a method, however you can do the following. cmd = "def sqr(x):\n return x**2\nself.sqr = sqr\n" http://docs.python.org/reference/datamodel.html : <http://docs.python.org/reference/datamodel.html> "It is also important to note that user-defined functions which are attributes of a class instance are not converted bound methods; this only happens when the function is an attribute of the class. " JM -- http://mail.python.org/mailman/listinfo/python-list
