Python3 - import导入模块，编辑的过程中动态加载模

import导入模块

cli的目录结构如下

➜  cli tree
.
├── __pycache__
│   └── test.cpython-36.pyc
├── demo1
├── demo2
│   ├── __pycache__
│   │   └── test2.cpython-36.pyc
│   └── test2.py
└── test.py

若直接在test.py中import test2则会报以下错误

➜  cli python3
Python 3.6.0 (default, Jan 23 2017, 14:53:49)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import test2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'test2'

通过以下方式查看import的搜索路径

>>> import sys
>>> sys.path
[
'', 
'/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python36.zip', 
'/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6',
'/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3
]

所以可以将test2.Py的路径加入上面的目录的方式来解决

>>> sys.path
[
'', 
'/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python36.zip', 
'/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6',
'/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3，
'./demo2/'
]
// 重新导入后没有再报错
>>> import test2
>>> 
>>> 

由于此时的test2.py文件内容为空

另开一个窗口编辑test2.py ,增加一个hello方法

15148114276369.jpg

回到左侧调用hello方法会报以下错误

>>> import test2
>>> test2.hello()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'test2' has no attribute 'hello'

当然可以通过推出在重新导入的方式是可以的，另一种方式就是该篇的第二个话题：动态加载

动态加载模块

场景：开了2个窗口同时编辑同一个文件，但又不想退出重进

>>> from imp import *
>>> reload(test2)
<module 'test2' from './demo2/test2.py'>

此时在调用hello方法即可

>>> test2.hello()
hello