effectivepython

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(2nd ed)

Expected result

Program should stop at 0:

3 ticks left
2 ticks left
1 ticks left
3 ticks left
2 ticks left
1 ticks left
0 ticks left

Actual result

Program runs on, down to -1:

3 ticks left
2 ticks left
1 ticks left
3 ticks left
2 ticks left
1 ticks left
0 ticks left
3 ticks left
3 ticks left
2 ticks left
1 ticks left
0 ticks left
-1 ticks left

Fix

Add an additional conditional break statement at the end of the run() function on both pages 136 and 137:

# page 136

def run():
    it = timer(4)
    while True:
        try:
            if check_for_reset():
                current = it.throw(Reset())
            else:
                current = next(it)
        except StopIteration:
            break
        else:
            announce(current)
            if current == 0:    # add this line
                break           # add this line

# page 137

def run():
    timer = Timer(4)
    for current in timer:
        if check_for_reset():
            timer.reset()
        announce(current)
        if current == 0:    # add this line
            break           # add this line