On Thu, 23 Apr 2015 09:12 pm, Jean-Michel Pichavant wrote: > If both list1 and fword are lists, you can also write > > list1 = list1 + fword > or > list1 += fword
You can, but you shouldn't since it risks being very slow, especially the first version. Repeated list addition has quadratic behaviour. It's okay if you only add a few lists, but if there are thousands or millions of them, it will be horribly slow. Using extend guarantees to modify the list in place and avoid unnecessary copying of data. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
