On Tue, Jan 9, 2018 at 3:25 AM, Cody Piersall <cody.piers...@gmail.com> wrote: >> Let's put it this way. Suppose that __eq__ existed and __ne__ didn't, >> just like with __contains__. Go ahead: sell the notion of __ne__. >> Pitch it, show why we absolutely need to allow this. Make sure you >> mention the potential confusion when subclassing. Be sure to show why >> it's okay for "not in" to force to boolean but "==" should allow any >> return value. > > __ne__ and __eq__ are important for building mask arrays in NumPy, > which allow complex indexing operations. A lot of NumPy's design was > inspired by MATLAB, so being able to index the same way as in MATLAB > is a pretty killer feature. > > Indexing an array using mask arrays like this is idiomatic: > > some_arr = np.array([-1, 0, 1, 2, 3, 4, 5, 2, -1, 3, -1, 6, 7, 3]) > valid = some_arr[some_arr != -1] > > Anybody with familiarity with NumPy appreciates that this is possible.
I've used it, and I'm familiar with it, and I'm still not sure that I appreciate it. But if it's there because of MATLAB, well, I guess that's what people want? ChrisA -- https://mail.python.org/mailman/listinfo/python-list
