python协程测试

协程理解的一个重点是，在定义执行的协程对象时，已经初始化了调用上下文，主要是环境变量。

# 实现即时计算range
def eager_range(up_to):
    """Create a list of integers, from 0 to up_to, exclusive."""
    sequence = []
    index = 0
    while index < up_to:
        sequence.append(index)
        index += 1
    return sequence

# lazy 方式生成range
def lazy_range(up_to):
    """Generator to return the sequence of integers from 0 to up_to, exclusive."""
    index = 0
    while index < up_to:
        yield index # 类似协和机制，返回Index, 同时调用把初始化好的调用栈保存好（包含当前up_to）
        print("icr index from %d"%index)
        index += 1


def jumping_range(up_to):
    """Generator for the sequence of integers from 0 to up_to, exclusive.
    Sending a value into the generator will shift the sequence by that amount.
    """
    index = 0
    while index < up_to:
        jump = yield index # jump是yield的返回值，也是send的参数, 如果是next触发则是None。
        if jump is None:
            jump = 1
        index += jump

def lazy_rangeV2(up_to):
    """Generator to return the sequence of integers from 0 to up_to, exclusive."""
    # index = 0 如在这里定义，则无法给gratuitous_refactor访问到
    def gratuitous_refactor():
        index = 0
        while index < up_to:
            yield index
            index += 1
    yield from gratuitous_refactor()


if __name__ == "__main__":
    print ("============testing realtime range============")
    r = eager_range(10)
    print(r)

    print ("============ testing lazy range ============")
    ins = lazy_range(10)
    ins1 = lazy_range(1000)
    print("lazy_range is a ", ins, ins1)
    print("lazy_range test next:", next(ins))
    print("lazy_range test next:", next(ins1))
    for i in ins:
        print ("lazy_range for value:",i)
    for i in ins1:
        print ("lazy_range1 for value:",i)

    print ("============ test jump range ============")
    iterator = jumping_range(5)
    print("jumping_range test next ", next(iterator))  # 0
    print("jumping_range test send ", iterator.send(2))  # 2
    print("jumping_range test next ", next(iterator))  # 3
    print("jumping_range test send ", iterator.send(-1))  # 2
    for x in iterator:
        print("jumping_range test for  ", x)  # 3, 4

    print ("============ test new lazy range ============")
    iterator = lazy_rangeV2(6)
    print("lazy_rangeV2 is a ", iterator)
    print("lay_rangeV2 test next ", next(iterator))