The Python Apprentice

The second stateful generator: distinct()

Now let's bring our second generator into the picture. This generator function, called distinct(), eliminates duplicate items by keeping track of which elements it's already seen in a set:

def distinct(iterable):    """Return unique items by eliminating duplicates.    Args:        iterable: The source of the items.    Yields:        Unique elements in order from 'iterable'.    """    seen = set()    for item in iterable:        if item in seen:            continue        yield item        seen.add(item)

In this generator we also make use of a control flow construct we have not previously seen: The continue keyword. The continue statement finishes the current iteration of the loop and begins the next iteration immediately. When executed in this case execution will ...