Python3基础 yield StopIteration.value获取函数的返回值

 

•        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会停止，保存数据并返回后面的数值
    yield a

    a += 1
    yield a

    a += 1
    yield a

    a += 1
    yield a

    # 需要这个返回值，可是....next()遇到yield就停了呀。再next抛异常，如何办？
    # 用StopIteration
    return "work done"

def main():
    test = yield_test()

    # 很标准的模板
    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

• [文档 - English] docs.python.org/3
• [文档 - 中文] docs.python.org/zh-cn/3
• [规范] www.python.org/dev/peps/pep-0008
• [规范] zh-google-styleguide.readthedocs.io/en/latest/google-python-styleguide/python_language_rules
• [源码] 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具有开源、跨平台、解释型、交互式等特性，值得学习。

Python的设计哲学：优雅，明确，简单。提倡用一种方法，最好是只有一种方法来做一件事。

代码的书写要遵守规范，这样有助于沟通和理解。

每种语言都有独特的思想，初学者需要转变思维、踏实践行、坚持积累。