Python3基础 def 函数要先定义再调用

 

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

 

code_1

"""
@Author : 行初心
@Date   : 2019/7/2
@Blog   : www.cnblogs.com/xingchuxin
"""

# 先调用，再定义函数。会报错！

say_hello()


def say_hello():
    print("hello world")

result_1

/home/coder/anaconda3/envs/py37/bin/python /home/coder/PycharmProjects/Base/demo.py
Traceback (most recent call last):
  File "/home/coder/PycharmProjects/Base/demo.py", line 8, in <module>
    say_hello()
NameError: name 'say_hello' is not defined

Process finished with exit code 1

 

code_2

"""
@Author : 行初心
@Date   : 2019/7/2
@Blog   : www.cnblogs.com/xingchuxin
"""


def say_hello():
    print("hello world")


say_hello()

result_2

/home/coder/anaconda3/envs/py37/bin/python /home/coder/PycharmProjects/Base/demo.py
hello world

Process finished with exit code 0

 

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。