Paul Hankin <[EMAIL PROTECTED]> writes: > On Oct 17, 10:03 pm, Debajit Adhikary <[EMAIL PROTECTED]> wrote: >> How does "a.extend(b)" compare with "a += b" when it comes to >> performance? Does a + b create a completely new list that it assigns >> back to a? If so, a.extend(b) would seem to be faster. How could I >> verify things like these? > > Use a += b rather than a.extend(b): I'm not sure what I was > thinking.
Why? a.extend(b) is at least as readable, and is guaranteed to extend the same list. In general, "a += b" can fall back to the slower "a = a + b" for sequences that don't support +=. -- http://mail.python.org/mailman/listinfo/python-list