On Wed, Mar 12, 2014 at 3:39 AM, Antoon Pardon <antoon.par...@rece.vub.ac.be> wrote: > The documentation is wrong at that point as the following code illustrates.
Either way it still has to do a getitem and a setitem, but if you have a more nested structure then the extra getitems are not repeated. For example, using your logdict class: >>> tab = logdict() >>> tab[1] = logdict() [1] <= <__main__.logdict object at 0x02A2E430> >>> tab[1][2] = logdict() [1] => <__main__.logdict object at 0x02A2E430> [2] <= <__main__.logdict object at 0x02A2EB10> >>> tab[1][2][3] = ['value'] [1] => <__main__.logdict object at 0x02A2E430> [2] => <__main__.logdict object at 0x02A2EB10> [3] <= ['value'] >>> tab[1][2][3] += [' with extra tail'] [1] => <__main__.logdict object at 0x02A2E430> [2] => <__main__.logdict object at 0x02A2EB10> [3] => ['value'] [3] <= ['value', ' with extra tail'] versus: >>> tab[1][2][3] = ['value'] [1] => <__main__.logdict object at 0x02A2E430> [2] => <__main__.logdict object at 0x02A2EB10> [3] <= ['value'] >>> tab[1][2][3] = tab[1][2][3] + [' with extra tail'] [1] => <__main__.logdict object at 0x02A2E430> [2] => <__main__.logdict object at 0x02A2EB10> [3] => ['value'] [1] => <__main__.logdict object at 0x02A2E430> [2] => <__main__.logdict object at 0x02A2EB10> [3] <= ['value', ' with extra tail'] As you can see the += version does two fewer getitem calls in this case. -- https://mail.python.org/mailman/listinfo/python-list
