Jim wrote: >Where did this type of structure come from: > >mat = ['a' for i in range(3)] ? > >This will produce a list of three elements but >I don't see reference for it in any of the books. > > > It's called a list comprehension and it appeared in Python 2.0. http://www.amk.ca/python/2.0/index.html#SECTION000600000000000000000 Jeremy Jones