Ezio Melotti <ezio.melo...@gmail.com> added the comment: >>> a = ['1'] >>> b = [] >>> c = a # now c and a refer to the same object >>> b.append(a) # this object is appended to b >>> a ['1'] >>> b [['1']] >>> c ['1'] # a and c refer to the same object you have in b # so all these ['1'] are actually the same object >>> a = ['2'] # now a refers to another object >>> c.extend(a) # and here you are extending the object referred by c # and the same object that you have in b >>> b [['1', '2']] >>> c ['1', '2'] # so this is correct >>> a ['2'] >>>
You can use id() to verify the identity of the objects, and read http://python.net/crew/mwh/hacks/objectthink.html for more information. ---------- nosy: +ezio.melotti stage: -> committed/rejected _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue14707> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
