ana sanchez wrote: > i found this when i read the source of a program in python: > > self.__chunks[start:end] = (chunk for i in xrange(start, end))
> what utility has to assign a generator to a slice??? ?the *final > result* isn't the same as this?: > > self.__chunks[start:end] = [chunk for i in xrange(start, end)] Whoever used the first variant probably was hoping that it was either faster or used less peak memory. I think the latter is wrong, and the former can easily be checked: $ python -m timeit -s'chunk = "yadda"; chunks = range(100); start = 20; end = 50' 'chunks[start:end] = (chunk for i in xrange(start, end))' 100000 loops, best of 3: 9.02 usec per loop $ python -m timeit -s'chunk = "yadda"; chunks = range(100); start = 20; end = 50' 'chunks[start:end] = [chunk for i in xrange(start, end)]' 100000 loops, best of 3: 4.16 usec per loop $ python -m timeit -s'chunk = "yadda"; chunks = range(100); start = 20; end = 50' 'chunks[start:end] = [chunk]*(end-start)' 1000000 loops, best of 3: 1.02 usec per loop -- http://mail.python.org/mailman/listinfo/python-list
