python导入和模块化

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# import os.path  # 注意os模块和path模块都加载了，但是dir()中只能拿到os
import os  # import后只能写模块名
import os.path
import os.path as osp  # 取别名,注意是os.path的别名，不是os的别名

print(dir())
# ['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__',
# '__package__', '__spec__', 'os']
# print(sorted(locals().keys()))
# print(sorted(globals().keys()))

print(os)
print(os.path)
print(osp)
print(os.path.exists('c:/tt'))  # 虽然没有导入path模块但是解释器替你做了，所以此语句可以执行
print(osp.exists('c:/text.txt'))

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def a():
    import pathlib
    print(dir())  # ['pathlib'] 受作用域的影响


a()
print('~~~~~~~~~~')
print(dir())
# ['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__',
# '__package__', '__spec__', 'a']

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from os import stat  # from后必须是模块,可以逗号分隔
from os.path import exists
from pathlib import Path
from pathlib import *
from functools import _make_key
# from os import path as osp
from functools import wraps as wr, update_wrapper

# from module import * | module | class | function | ...
print(dir())

from os.path import exists  # 注意from后的模块并不导入，只是加载
import os.path


print(exists)

print(os.path.exists)
print(os.path.__dict__['exists'])
print(getattr(os.path, 'exists'))
# <function exists at 0x0000000001DE31E0>

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from pathlib import Path
import pathlib as pl


print(id(Path), Path)
# 42604072 <class 'pathlib.Path'>
print(id(pl.Path), pl.Path)
# 42604072 <class 'pathlib.Path'>
p1 = Path()
p2 = pl.Path()  # 注意p1和p2肯定不一样
print(Path is pl.Path)  # True

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import pathlib
import sys


print(*sys.path, sep='n')
print(pathlib.Path.__doc__)
print(sys.path)
"""C:UsersAdministratorPycharmProjects面向对象进阶venvScriptspython.exe C:/Users/Administrator/PycharmProjects/面向对象进阶/模块化/导入.py
C:UsersAdministratorPycharmProjects面向对象进阶模块化
C:UsersAdministratorPycharmProjects面向对象进阶
C:UsersAdministratorPycharmProjects面向对象进阶venvScriptspython36.zip
C:UsersAdministratorAppDataLocalProgramsPythonPython36DLLs
C:UsersAdministratorAppDataLocalProgramsPythonPython36lib
C:UsersAdministratorAppDataLocalProgramsPythonPython36
C:UsersAdministratorPycharmProjects面向对象进阶venv
C:UsersAdministratorPycharmProjects面向对象进阶venvlibsite-packages
C:UsersAdministratorPycharmProjects面向对象进阶venvlibsite-packagessetuptools-39.1.0-py3.6.egg
C:UsersAdministratorPycharmProjects面向对象进阶venvlibsite-packagespip-10.0.1-py3.6.egg
PurePath subclass that can make system calls.

    Path represents a filesystem path but unlike PurePath, also offers
    methods to do system calls on path objects. Depending on your system,
    instantiating a Path will return either a PosixPath or a WindowsPath
    object. You can also instantiate a PosixPath or WindowsPath directly,
    but cannot instantiate a WindowsPath on a POSIX system or vice versa.
    
['C:\Users\Administrator\PycharmProjects\面向对象进阶\模块化', 'C:\Users\Administrator\PycharmProjects\面向对象进阶', 'C:\Users\Administrator\PycharmProjects\面向对象进阶\venv\Scripts\python36.zip', 'C:\Users\Administrator\AppData\Local\Programs\Python\Python36\DLLs', 'C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib', 'C:\Users\Administrator\AppData\Local\Programs\Python\Python36', 'C:\Users\Administrator\PycharmProjects\面向对象进阶\venv', 'C:\Users\Administrator\PycharmProjects\面向对象进阶\venv\lib\site-packages', 'C:\Users\Administrator\PycharmProjects\面向对象进阶\venv\lib\site-packages\setuptools-39.1.0-py3.6.egg', 'C:\Users\Administrator\PycharmProjects\面向对象进阶\venv\lib\site-packages\pip-10.0.1-py3.6.egg']

"""

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# import a  # 注意目录没有__file__属性
#
#
# print(dir(a))
# print(type(a))
# print(a)
# print(a.__path__)
# print(a.x)


# import m  # 注意只加载m，不会递归加载
# from m import m1
# import m.m1
# import m.m2.m21
import m
from m.m2 import m22  # 此时m2不在当前名词空间中
import sys


print(dir())  # 加载了m和m1，当前名词空间中只有m
# print(m.m1)

print(list(filter(lambda x: x.startswith('m'), sys.modules.keys())))
print(m.abc)
print(m.m2.y)
print(m.m2.__dict__.keys())
print(m.m2.m22)

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from . import d  # 有相对导入的模块不能作为主模块了，直接运行会报错
from .. import e

# d = 1000
print(d.__file__)
print(e.__file__)

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print(__name__)
A = 5
_B = 20
__C = 300

print(dir())
# ['A', '_B', '__C', '__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', 
# '__loader__', '__name__', '__package__', '__spec__']

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# import test
#
# from test import A, _B, __C
from test import *  # 最前面带下划线的是无法导入的


print(dir())

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# test.py
print(__name__)

__all__ = ['X', '_Y']

X = 5
_Y = 20
__Z = 300

__my__ = 500


def _a():
    pass


class __A:
    pass


print(dir())

# test2.py
from test import *  # 只能导入__all__列表中的名称，即X, _Y
import test


print(dir())
print(test._Y)