Python3基礎 yield StopIteration.value獲取函數的返回值

 

•        Python : 3.7.3
•          OS : Ubuntu 18.04.2 LTS
•         IDE : pycharm-community-2019.1.3
•       Conda : 4.7.5
•    typesetting : Markdown

 

code

"""
@Author : 行初心
@Date   : 2019/7/6
@Blog   : www.cnblogs.com/xingchuxin
@Gitee  : gitee.com/zhichengjiu
"""


def yield_test():
    a = 1
    # next() 遇到yield會停止，保存數據並返回后面的數值
    yield a

    a += 1
    yield a

    a += 1
    yield a

    a += 1
    yield a

    # 需要這個返回值，可是....next()遇到yield就停了呀。再next拋異常，如何辦？
    # 用StopIteration
    return "work done"


def main():
    test = yield_test()

    # 很標准的模板
    while True:
        try:
            x = test.__next__()
            print(x)
        except StopIteration as e:
            # e.value 就是 return 返回的值
            print("return value is", e.value)
            break


if __name__ == '__main__':
    main()

 

result

/home/coder/anaconda3/envs/py37/bin/python /home/coder/PycharmProjects/NumericalComputation/demo.py
1
2
3
4
return value is work done

Process finished with exit code 0

 

source_code

class StopIteration(Exception):
    """ Signal the end from iterator.__next__(). """
    def __init__(self, *args, **kwargs): # real signature unknown
        pass

    value = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
    """generator return value"""

 

resource

• [文檔 - English] docs.python.org/3
• [文檔 - 中文] docs.python.org/zh-cn/3
• [規范] www.python.org/dev/peps/pep-0008
• [規范] zh-google-styleguide.readthedocs.io/en/latest/google-python-styleguide/python_language_rules
• [源碼] www.python.org/downloads/source
• [ PEP ] www.python.org/dev/peps
• [平台] www.cnblogs.com
• [平台] gitee.com

 

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Python具有開源、跨平台、解釋型、交互式等特性，值得學習。
Python的設計哲學：優雅，明確，簡單。提倡用一種方法，最好是只有一種方法來做一件事。
代碼的書寫要遵守規范，這樣有助於溝通和理解。
每種語言都有獨特的思想，初學者需要轉變思維、踏實踐行、堅持積累。