Bengt Richter wrote: > If you want to terminate a generator expression after the first sequence of > elements > satisfying a condition, and you don't want to use takewhile, I don't know of > a gotcha > to prevent you from just raising StopIteration, using an expression that will > do that, e.g., > > >>> list (x for x in xrange(20) if x<5 or iter([]).next()) > [0, 1, 2, 3, 4] > > Or a bit more readably: > >>> def stop(): raise StopIteration > ... > >>> list (x for x in xrange(20) if x<5 or stop()) > [0, 1, 2, 3, 4] > > IOW, your "when condition(x)" (IIUIC) can be spelled "if condition(x) or > stop()" If it is a single loop, takewhile/dropwhile is perfectly fine but as I mentioned in another post, it is nested and the condition needs surrounding scope so seperate function and StopIteration doesn't work as it breaks out of the whole thing expression.
takewhile/dropwhile still works in this case(because of the lambda which sees the surrounding scope). -- http://mail.python.org/mailman/listinfo/python-list
