James Stroud wrote: > Steven Woody wrote: >> Hi, >> >> In the book Python Essential Reference, Chapter 3, when talking about >> extended slicing, it gives an example: a = m[0:10, 3:20]. But I >> don't understand how the 'm' was defined. What should it looks like? > > m could be an instance of the Krayzee class. > > py> class Krayzee(object): > ... def __getitem__(self, i): > ... try: > ... r = ['WTF?' for j in i] > ... except: > ... r = 'WTF?' > ... return r > ... > py> m = Krayzee() > py> m[1:2:3, 4:5:6] > ['WTF?', 'WTF?'] > py> m['your moms'] > ['WTF?', 'WTF?', 'WTF?', 'WTF?', 'WTF?', 'WTF?', 'WTF?', 'WTF?', 'WTF?'] > > I'm not sure what this is supposed to prove. It might be more helpful to show what's actually going on ...
>>> class k(object): ... def __getitem__(self, i): ... try: ... r = [j for j in i] ... except Exception, e: ... print i, ":", e ... r = i ... return r ... >>> m = k() >>> m[1:2:3, 4:5:6] [slice(1, 2, 3), slice(4, 5, 6)] >>> m["help!"] ['h', 'e', 'l', 'p', '!'] >>> As you can see, no exceptions are raised here, and the x:y:z notation introduces a slice object, which the code doesn't handle in any way shape or form. regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list
