If you have Numeric or numpy installed try this: #import Numeric as N import numpy as N
a = range(10) b = N.arange(10) a.__iadd__(b) print a Result: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9] Contrast the returned output with import numpy as N a = range(10) b = N.arange(10) a += b print a Result: [ 0 2 4 6 8 10 12 14 16 18] Having "a+=b" and "a.__iadd__(b)" do different things seems like an unfortunate bug. It seems to me that the problem is that the INPLACE_ADD and INPLACE_MULTIPLY cases in ceval.c use PyNumber_InPlace<YYY> instead of trying PySequence_InPlace<YYY> when the object doesn't support the in-place number protocol. I could submit a patch if there is agreement that this is a problem. -Travis _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com