On Sat, Apr 18, 2015 at 3:28 PM, Bill Allen <walle...@gmail.com> wrote: > On Apr 18, 2015 7:50 AM, "Peter Otten" <__pete...@web.de> wrote: > >> Bill Allen wrote: >> >> > Everyone that responded, >> > >> > Thanks very much for the excellent explanations! The distinction between >> > a reference to an object and a seperate copy of the object is quite clear >> > now. >> >> You can test your newfound knowledge by predicting the output of the >> following script: >> >> >> a = [1, ["x", "y"], 3] >> b = a[:] >> >> a[1][1] = "hello!" >> >> print(a) # [1, ['x', 'hello!'], 3] >> print(b) # what will that print? >> >> Think twice before you answer. What is copied, what is referenced?
> print(b) will print the original copy of a which b now references which is > [1, ["x", "y"], 3] Uh, oh! You should have checked your work in the interpreter before replying! Peter is being very tricky!! (At least for me...) Look again at that list inside of a list and... boB P.S.: Watch out for top-posting. That tends to get peopled riled. I moved your response back into the normal flow of the interleaved conversation. _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
