Python包模块化调用方式详解
作者：尹正杰
版权声明：原创作品，谢绝转载！否则将追究法律责任。
一般来说，编程语言中，库、包、模块是同一种概念，是代码组织方式。 Python中只有一种模块对象类型，但是为了模块化组织模块的便利，提供了"包"的概念。
模块module，指的是Python的源代码文件。 包package，指的是模块组织在一起的和包名同名的目录及其相关文件。
一.导入语句
1 #！/usr/bin/env python 2 #_*_conding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie 5 6 import os 7 import pathlib as p1 #倒入模块使用别名 8 from os.path import exists #加载、初始化os、os.path模块，exists加入本地名词空间并绑定 9 10 """ 11 总结 12 找到from子句中指定的模块，加载并初始化它(注意不是导入) 13 14 对于import子句后的名称 15 1>.先查from子句导入的模块是否具有该名称的属性 16 2>.如果不是，则尝试导入该名称的子模块 17 3>.还没有找到，则抛出ImportError异常 18 4>.这个名称保存到本地名词空间中，如果有as子句，则使用as子句后的名称 19 """ 20 21 if exists('o:/t'): 22 print('Found') 23 else: 24 print('Not Found') 25 print(dir()) 26 print(exists) 27 28 # 4种方式获得同一个对象exist 29 print(os.path.exists) 30 print(exists) 31 print(os.path.__dict__['exists']) # 字符串 32 print(getattr(os.path, 'exists')) # 字符串 33 34 35 print(p1) 36 print(p1.Path,id(p1.Path)) 37 print(dir())
Not Found ['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'exists', 'os', 'p1'] <function exists at 0x1006f9d08> <function exists at 0x1006f9d08> <function exists at 0x1006f9d08> <function exists at 0x1006f9d08> <function exists at 0x1006f9d08> <module 'pathlib' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pathlib.py'> <class 'pathlib.Path'> 4328656856 ['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'exists', 'os', 'p1']
二.自定义模块
1>.自定义模块命名规范
(1)模块名就是文件名,"*.py"文件就是一个模块 (2)模块名必须符合标识符的要求，是非数字开头的字母、数字和下划线的组合。test-module.py这样的文件名不能作为模块名。也不要使用中文。 (3)不要使用系统模块名来避免冲突，除非你明确知道这个模块名的用途 (4)通常模块名为全小写，下划线来分割
2>.案例演示
1 #！/usr/bin/env python 2 #_*_conding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie 5 6 class Point: 7 def __init__(self,x,y): 8 self.x = x 9 self.y = y 10 11 def showModule(self): 12 print(1,self.__module__,self) 13 print(2,self.__dict__) 14 print(3,self.__class__.__dict__) 15 print(4,self.__class__.__name__) 16 17 18 def __repr__(self): 19 return "Point(x = {},y = {})".format(self.x,self.y) 20 21 p = Point(10,20) 22 print(p)
#！/usr/bin/env python #_*_conding:utf-8_*_ #@author :yinzhengjie #blog:http://www.cnblogs.com/yinzhengjie import test01 a = test01.Point(300,1000) a.showModule()
1 #！/usr/bin/env python 2 #_*_conding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie 5 6 from test01 import Point as p1 7 8 9 b = p1(20,30) 10 b.showModule()
三.模块搜索顺序
1 #！/usr/bin/env python 2 #_*_conding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie 5 6 import sys 7 8 """ 9 使用 sys.path 查看搜索顺序,路径顺序为 10 1.程序主目录，程序运行的主程序脚本所在的目录 11 2.PYTHONPATH目录，环境变量PYTHONPATH设置的目录也是搜索模块的路径 3. 标准库目录，Python自带的库模块所在目录 12 13 温馨提示: 14 sys.path可以被修改，增加新的目录 15 """ 16 print(*sys.path,sep=" ")
/yinzhengjie/python/devops/python基础/08.模块化 /yinzhengjie/python/devops /Applications/PyCharm.app/Contents/helpers/pycharm_display /Library/Frameworks/Python.framework/Versions/3.7/lib/python37.zip /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7 /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/lib-dynload /yinzhengjie/python/devops/venv/lib/python3.7/site-packages /yinzhengjie/python/devops/venv/lib/python3.7/site-packages/setuptools-40.8.0-py3.7.egg /yinzhengjie/python/devops/venv/lib/python3.7/site-packages/pip-19.0.3-py3.7.egg /Applications/PyCharm.app/Contents/helpers/pycharm_matplotlib_backend
四.模块的重复导入
1 #！/usr/bin/env python 2 #_*_conding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie 5 6 import sys 7 print(sys.modules) #所有加载的模块都会记录在"sys.modules"中,sys.modules是存储已经加载过的所有模块的字典。 8 9 import test01 #第一次加载"test01"模块 10 11 print("local module") 12 print(sys.modules) #打印"sys.modules"可以看到os,os.path都已经加载了。 13 14 import test01 15 import test01 #我们多次对"test01"模块进行倒入，然而并不会产生重复倒入对现象。 16 17 print(sys.modules)
{'sys': <module 'sys' (built-in)>, 'builtins': <module 'builtins' (built-in)>, '_frozen_importlib': <module '_frozen_importlib' (frozen)>, '_imp': <module '_imp' (built-in)>, '_thread': <module '_thread' (built-in)>, '_warnings': <module '_warnings' (built-in)>, '_weakref': <module '_weakref' (built-in)>, '_frozen_importlib_external': <module '_frozen_importlib_external' (frozen)>, '_io': <module 'io' (built-in)>, 'marshal': <module 'marshal' (built-in)>, 'posix': <module 'posix' (built-in)>, 'zipimport': <module 'zipimport' (built-in)>, 'encodings': <module 'encodings' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/__init__.py'>, 'codecs': <module 'codecs' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/codecs.py'>, '_codecs': <module '_codecs' (built-in)>, 'encodings.aliases': <module 'encodings.aliases' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/aliases.py'>, 'encodings.utf_8': <module 'encodings.utf_8' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/utf_8.py'>, '_signal': <module '_signal' (built-in)>, '__main__': <module '__main__' from '/yinzhengjie/python/devops/python基础/08.模块化/test02.py'>, 'encodings.latin_1': <module 'encodings.latin_1' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/latin_1.py'>, 'io': <module 'io' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/io.py'>, 'abc': <module 'abc' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/abc.py'>, '_weakrefset': <module '_weakrefset' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_weakrefset.py'>, 'site': <module 'site' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site.py'>, 'os': <module 'os' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/os.py'>, 'errno': <module 'errno' (built-in)>, 'stat': <module 'stat' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/stat.py'>, '_stat': <module '_stat' (built-in)>, 'posixpath': <module 'posixpath' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/posixpath.py'>, 'genericpath': <module 'genericpath' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/genericpath.py'>, 'os.path': <module 'posixpath' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/posixpath.py'>, '_collections_abc': <module '_collections_abc' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_collections_abc.py'>, '_sitebuiltins': <module '_sitebuiltins' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_sitebuiltins.py'>, '_bootlocale': <module '_bootlocale' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_bootlocale.py'>, '_locale': <module '_locale' (built-in)>, 'encodings.cp437': <module 'encodings.cp437' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/cp437.py'>, 'sitecustomize': <module 'sitecustomize' from '/Applications/PyCharm.app/Contents/helpers/pycharm_matplotlib_backend/sitecustomize.py'>}
Point(x = 10,y = 20)
local module
{'sys': <module 'sys' (built-in)>, 'builtins': <module 'builtins' (built-in)>, '_frozen_importlib': <module '_frozen_importlib' (frozen)>, '_imp': <module '_imp' (built-in)>, '_thread': <module '_thread' (built-in)>, '_warnings': <module '_warnings' (built-in)>, '_weakref': <module '_weakref' (built-in)>, '_frozen_importlib_external': <module '_frozen_importlib_external' (frozen)>, '_io': <module 'io' (built-in)>, 'marshal': <module 'marshal' (built-in)>, 'posix': <module 'posix' (built-in)>, 'zipimport': <module 'zipimport' (built-in)>, 'encodings': <module 'encodings' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/__init__.py'>, 'codecs': <module 'codecs' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/codecs.py'>, '_codecs': <module '_codecs' (built-in)>, 'encodings.aliases': <module 'encodings.aliases' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/aliases.py'>, 'encodings.utf_8': <module 'encodings.utf_8' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/utf_8.py'>, '_signal': <module '_signal' (built-in)>, '__main__': <module '__main__' from '/yinzhengjie/python/devops/python基础/08.模块化/test02.py'>, 'encodings.latin_1': <module 'encodings.latin_1' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/latin_1.py'>, 'io': <module 'io' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/io.py'>, 'abc': <module 'abc' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/abc.py'>, '_weakrefset': <module '_weakrefset' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_weakrefset.py'>, 'site': <module 'site' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site.py'>, 'os': <module 'os' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/os.py'>, 'errno': <module 'errno' (built-in)>, 'stat': <module 'stat' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/stat.py'>, '_stat': <module '_stat' (built-in)>, 'posixpath': <module 'posixpath' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/posixpath.py'>, 'genericpath': <module 'genericpath' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/genericpath.py'>, 'os.path': <module 'posixpath' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/posixpath.py'>, '_collections_abc': <module '_collections_abc' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_collections_abc.py'>, '_sitebuiltins': <module '_sitebuiltins' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_sitebuiltins.py'>, '_bootlocale': <module '_bootlocale' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_bootlocale.py'>, '_locale': <module '_locale' (built-in)>, 'encodings.cp437': <module 'encodings.cp437' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/cp437.py'>, 'sitecustomize': <module 'sitecustomize' from '/Applications/PyCharm.app/Contents/helpers/pycharm_matplotlib_backend/sitecustomize.py'>, 'test01': <module 'test01' from '/yinzhengjie/python/devops/python基础/08.模块化/test01.py'>}
{'sys': <module 'sys' (built-in)>, 'builtins': <module 'builtins' (built-in)>, '_frozen_importlib': <module '_frozen_importlib' (frozen)>, '_imp': <module '_imp' (built-in)>, '_thread': <module '_thread' (built-in)>, '_warnings': <module '_warnings' (built-in)>, '_weakref': <module '_weakref' (built-in)>, '_frozen_importlib_external': <module '_frozen_importlib_external' (frozen)>, '_io': <module 'io' (built-in)>, 'marshal': <module 'marshal' (built-in)>, 'posix': <module 'posix' (built-in)>, 'zipimport': <module 'zipimport' (built-in)>, 'encodings': <module 'encodings' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/__init__.py'>, 'codecs': <module 'codecs' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/codecs.py'>, '_codecs': <module '_codecs' (built-in)>, 'encodings.aliases': <module 'encodings.aliases' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/aliases.py'>, 'encodings.utf_8': <module 'encodings.utf_8' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/utf_8.py'>, '_signal': <module '_signal' (built-in)>, '__main__': <module '__main__' from '/yinzhengjie/python/devops/python基础/08.模块化/test02.py'>, 'encodings.latin_1': <module 'encodings.latin_1' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/latin_1.py'>, 'io': <module 'io' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/io.py'>, 'abc': <module 'abc' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/abc.py'>, '_weakrefset': <module '_weakrefset' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_weakrefset.py'>, 'site': <module 'site' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site.py'>, 'os': <module 'os' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/os.py'>, 'errno': <module 'errno' (built-in)>, 'stat': <module 'stat' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/stat.py'>, '_stat': <module '_stat' (built-in)>, 'posixpath': <module 'posixpath' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/posixpath.py'>, 'genericpath': <module 'genericpath' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/genericpath.py'>, 'os.path': <module 'posixpath' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/posixpath.py'>, '_collections_abc': <module '_collections_abc' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_collections_abc.py'>, '_sitebuiltins': <module '_sitebuiltins' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_sitebuiltins.py'>, '_bootlocale': <module '_bootlocale' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/_bootlocale.py'>, '_locale': <module '_locale' (built-in)>, 'encodings.cp437': <module 'encodings.cp437' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/encodings/cp437.py'>, 'sitecustomize': <module 'sitecustomize' from '/Applications/PyCharm.app/Contents/helpers/pycharm_matplotlib_backend/sitecustomize.py'>, 'test01': <module 'test01' from '/yinzhengjie/python/devops/python基础/08.模块化/test01.py'>}
五.模块运行
1>.if __name__ == '__main__' 的用途
1 #！/usr/bin/env python 2 #_*_conding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie 5 6 class Point: 7 def __init__(self,x,y): 8 self.x = x 9 self.y = y 10 11 def showModule(self): 12 print(1,self.__module__,self) 13 print(2,self.__dict__) 14 print(3,self.__class__.__dict__) 15 print(4,self.__class__.__name__) 16 17 18 def __repr__(self): 19 return "Point(x = {},y = {})".format(self.x,self.y) 20 21 p = Point(10,20) 22 print(p)
#！/usr/bin/env python #_*_conding:utf-8_*_ #@author :yinzhengjie #blog:http://www.cnblogs.com/yinzhengjie import test01 """ if __name__ == '__main__': 用途 1.本模块的功能测试 对于非主模块，测试本模块内的函数、类 2.避免主模块变更的副作用 顶层代码，没有封装，主模块使用时没有问题。但是，一旦有了新的主模块，老的主模块成了被导入模块， 由于原来代码没有封装，一并执行了。 """ if __name__ == '__main__': print("in __main__") else: print("in imported module")
Point(x = 10,y = 20) in __main__
2>.模块的属性
1 #！/usr/bin/env python 2 #_*_conding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie 5 6 import test01 as t1 7 8 """ 9 模块的属性如下: 10 __file__ 11 字符串，源文件路径 12 __cached__ 13 字符串，编译后的字节码文件路径 14 __spec__ 15 显示模块的规范 16 __name__ 17 模块名 18 __package__ 19 当模块是包，同 __name__ ;否则，可以设置为顶级模块的空字符串 20 """ 21 22 for k,v in t1.__dict__.items(): 23 print(k,str(v)[:80]) 24 25 print(dir(t1)) 26 27 for name in dir(t1): 28 print(getattr(t1,name))
Point(x = 10,y = 20) __name__ test01 __doc__ None __package__ __loader__ <_frozen_importlib_external.SourceFileLoader object at 0x1021610b8> __spec__ ModuleSpec(name='test01', loader=<_frozen_importlib_external.SourceFileLoader ob __file__ /yinzhengjie/python/devops/python基础/08.模块化/test01.py __cached__ /yinzhengjie/python/devops/python基础/08.模块化/__pycache__/test01.cpython-37.pyc __builtins__ {'__name__': 'builtins', '__doc__': "Built-in functions, exceptions, and other o Point <class 'test01.Point'> p Point(x = 10,y = 20) ['Point', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'p'] <class 'test01.Point'> {'__name__': 'builtins', '__doc__': "Built-in functions, exceptions, and other objects. Noteworthy: None is the `nil' object; Ellipsis represents `...' in slices.", '__package__': '', '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': ModuleSpec(name='builtins', loader=<class '_frozen_importlib.BuiltinImporter'>), '__build_class__': <built-in function __build_class__>, '__import__': <built-in function __import__>, 'abs': <built-in function abs>, 'all': <built-in function all>, 'any': <built-in function any>, 'ascii': <built-in function ascii>, 'bin': <built-in function bin>, 'callable': <built-in function callable>, 'chr': <built-in function chr>, 'compile': <built-in function compile>, 'delattr': <built-in function delattr>, 'dir': <built-in function dir>, 'divmod': <built-in function divmod>, 'eval': <built-in function eval>, 'exec': <built-in function exec>, 'format': <built-in function format>, 'getattr': <built-in function getattr>, 'globals': <built-in function globals>, 'hasattr': <built-in function hasattr>, 'hash': <built-in function hash>, 'hex': <built-in function hex>, 'id': <built-in function id>, 'input': <built-in function input>, 'isinstance': <built-in function isinstance>, 'issubclass': <built-in function issubclass>, 'iter': <built-in function iter>, 'len': <built-in function len>, 'locals': <built-in function locals>, 'max': <built-in function max>, 'min': <built-in function min>, 'next': <built-in function next>, 'oct': <built-in function oct>, 'ord': <built-in function ord>, 'pow': <built-in function pow>, 'print': <built-in function print>, 'repr': <built-in function repr>, 'round': <built-in function round>, 'setattr': <built-in function setattr>, 'sorted': <built-in function sorted>, 'sum': <built-in function sum>, 'vars': <built-in function vars>, 'None': None, 'Ellipsis': Ellipsis, 'NotImplemented': NotImplemented, 'False': False, 'True': True, 'bool': <class 'bool'>, 'memoryview': <class 'memoryview'>, 'bytearray': <class 'bytearray'>, 'bytes': <class 'bytes'>, 'classmethod': <class 'classmethod'>, 'complex': <class 'complex'>, 'dict': <class 'dict'>, 'enumerate': <class 'enumerate'>, 'filter': <class 'filter'>, 'float': <class 'float'>, 'frozenset': <class 'frozenset'>, 'property': <class 'property'>, 'int': <class 'int'>, 'list': <class 'list'>, 'map': <class 'map'>, 'object': <class 'object'>, 'range': <class 'range'>, 'reversed': <class 'reversed'>, 'set': <class 'set'>, 'slice': <class 'slice'>, 'staticmethod': <class 'staticmethod'>, 'str': <class 'str'>, 'super': <class 'super'>, 'tuple': <class 'tuple'>, 'type': <class 'type'>, 'zip': <class 'zip'>, '__debug__': True, 'BaseException': <class 'BaseException'>, 'Exception': <class 'Exception'>, 'TypeError': <class 'TypeError'>, 'StopAsyncIteration': <class 'StopAsyncIteration'>, 'StopIteration': <class 'StopIteration'>, 'GeneratorExit': <class 'GeneratorExit'>, 'SystemExit': <class 'SystemExit'>, 'KeyboardInterrupt': <class 'KeyboardInterrupt'>, 'ImportError': <class 'ImportError'>, 'ModuleNotFoundError': <class 'ModuleNotFoundError'>, 'OSError': <class 'OSError'>, 'EnvironmentError': <class 'OSError'>, 'IOError': <class 'OSError'>, 'EOFError': <class 'EOFError'>, 'RuntimeError': <class 'RuntimeError'>, 'RecursionError': <class 'RecursionError'>, 'NotImplementedError': <class 'NotImplementedError'>, 'NameError': <class 'NameError'>, 'UnboundLocalError': <class 'UnboundLocalError'>, 'AttributeError': <class 'AttributeError'>, 'SyntaxError': <class 'SyntaxError'>, 'IndentationError': <class 'IndentationError'>, 'TabError': <class 'TabError'>, 'LookupError': <class 'LookupError'>, 'IndexError': <class 'IndexError'>, 'KeyError': <class 'KeyError'>, 'ValueError': <class 'ValueError'>, 'UnicodeError': <class 'UnicodeError'>, 'UnicodeEncodeError': <class 'UnicodeEncodeError'>, 'UnicodeDecodeError': <class 'UnicodeDecodeError'>, 'UnicodeTranslateError': <class 'UnicodeTranslateError'>, 'AssertionError': <class 'AssertionError'>, 'ArithmeticError': <class 'ArithmeticError'>, 'FloatingPointError': <class 'FloatingPointError'>, 'OverflowError': <class 'OverflowError'>, 'ZeroDivisionError': <class 'ZeroDivisionError'>, 'SystemError': <class 'SystemError'>, 'ReferenceError': <class 'ReferenceError'>, 'MemoryError': <class 'MemoryError'>, 'BufferError': <class 'BufferError'>, 'Warning': <class 'Warning'>, 'UserWarning': <class 'UserWarning'>, 'DeprecationWarning': <class 'DeprecationWarning'>, 'PendingDeprecationWarning': <class 'PendingDeprecationWarning'>, 'SyntaxWarning': <class 'SyntaxWarning'>, 'RuntimeWarning': <class 'RuntimeWarning'>, 'FutureWarning': <class 'FutureWarning'>, 'ImportWarning': <class 'ImportWarning'>, 'UnicodeWarning': <class 'UnicodeWarning'>, 'BytesWarning': <class 'BytesWarning'>, 'ResourceWarning': <class 'ResourceWarning'>, 'ConnectionError': <class 'ConnectionError'>, 'BlockingIOError': <class 'BlockingIOError'>, 'BrokenPipeError': <class 'BrokenPipeError'>, 'ChildProcessError': <class 'ChildProcessError'>, 'ConnectionAbortedError': <class 'ConnectionAbortedError'>, 'ConnectionRefusedError': <class 'ConnectionRefusedError'>, 'ConnectionResetError': <class 'ConnectionResetError'>, 'FileExistsError': <class 'FileExistsError'>, 'FileNotFoundError': <class 'FileNotFoundError'>, 'IsADirectoryError': <class 'IsADirectoryError'>, 'NotADirectoryError': <class 'NotADirectoryError'>, 'InterruptedError': <class 'InterruptedError'>, 'PermissionError': <class 'PermissionError'>, 'ProcessLookupError': <class 'ProcessLookupError'>, 'TimeoutError': <class 'TimeoutError'>, 'open': <built-in function open>, 'quit': Use quit() or Ctrl-D (i.e. EOF) to exit, 'exit': Use exit() or Ctrl-D (i.e. EOF) to exit, 'copyright': Copyright (c) 2001-2017 Python Software Foundation. All Rights Reserved. Copyright (c) 2000 BeOpen.com. All Rights Reserved. Copyright (c) 1995-2001 Corporation for National Research Initiatives. All Rights Reserved. Copyright (c) 1991-1995 Stichting Mathematisch Centrum, Amsterdam. All Rights Reserved., 'credits': Thanks to CWI, CNRI, BeOpen.com, Zope Corporation and a cast of thousands for supporting Python development. See www.python.org for more information., 'license': Type license() to see the full license text, 'help': Type help() for interactive help, or help(object) for help about object.} /yinzhengjie/python/devops/python基础/08.模块化/__pycache__/test01.cpython-37.pyc None /yinzhengjie/python/devops/python基础/08.模块化/test01.py <_frozen_importlib_external.SourceFileLoader object at 0x1021610b8> test01 ModuleSpec(name='test01', loader=<_frozen_importlib_external.SourceFileLoader object at 0x1021610b8>, origin='/yinzhengjie/python/devops/python基础/08.模块化/test01.py') Point(x = 10,y = 20)
六.包
pycharm中，创建Directory和创建Python package不同，前者是创建普通的目录，后者是创建一个带有 __init__.py 文件的目录即包。
Python中，目录可以作为模块，这就是包，不过代码需要写在该目录下 __init__.py 中。
七.子模块
1>.包目录下的py文件，子目录都是其子模块，目录结构如下图所示
2>.在上图的包中“setup.py”文件编写测试代码
1 #！/usr/bin/env python 2 #_*_conding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie 5 6 import hdfs 7 import mapreduce.yarn 8 from mapreduce import yarn 9 from hdfs.namenode import NameNode 10 11 print(__file__) #打印当前文件名称 12 13 print("{0}我是分割线{0}".format("*" * 20)) 14 15 print(dir()) 16 17 print("{0}我是分割线{0}".format("*" * 20)) 18 19 import sys 20 print(sorted(filter(lambda x:x.startswith("m"),sys.modules.keys())))
in hadoop.hdfs in hadoop.yarn in haoop.hdfs.namenode /yinzhengjie/python/devops/python基础/08.模块化/hadoop/setup.py ********************我是分割线******************** ['NameNode', '__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'hdfs', 'mapreduce', 'yarn'] ********************我是分割线******************** ['mapreduce', 'mapreduce.yarn', 'marshal']
八.模块和包的总结
包能够更好的组织模块，尤其是大的模块，其代码行数很多，可以把它拆分成很多子模块，便于使用某些功能就加载相应的子模块。
包目录中 __init__.py 是在包第一次导入的时候就会执行，内容可以为空，也可以是用于该包初始化工作的代码， 最好不要删除它(低版本不可删除 __init__.py 文件) 导入子模块一定会加载父模块，但是导入父模块一定不会导入子模块
包目录之间只能使用.点号作为间隔符，表示模块及其子模块的层级关系
模块也是封装，如同类、函数，不过它能够封装变量、类、函数。
模块就是命名空间，其内部的顶层标识符，都是它的属性，可以通过 __dict__ 或dir(module)查看。
包也是模块，但模块不一定是包，包是特殊的模块，是一种组织方式，它包含 __path__ 属性
from json import encoder 之后， json.dump 函数用不了，为什么? import json.encoder 之后呢? json.dump 函数能用吗? 原因是： from json import encoder之后，当前名词空间没有json，但是json模块已经加载过了，没有json的引用， 无法使用dump函数。 import json.encoder也加载json模块，但是当前名词空间有json，因此可以调用json.dump。
九.绝对导入和相对导入
1>.绝对导入
在import语句或者from导入模块，模块名称最前面不是以.点开头的
绝对导入总是去模块搜索路径中找，当然会查看一下该模块是否已经加载
2>.相对导入
只在包内使用，且只能用在from语句中，相对导入，更像是目录操作。 使用.点号，表示当前目录内 ..表示上一级目录 不要在顶层模块中使用相对导入 举例a.b.c模块，a、b是目录，c是模块c.py，c的代码中，使用 from . import d # imports a.b.d from .. import e # imports a.e from .d import x # a.b.d.x from ..e import x # a.e.x ... 三点表示上上一级 温馨提示: 一旦一个模块中使用相对导入，就不可以作为主模块运行了。 测试一下有相对导入语句的模块，能够直接运行吗?答案是否定的，很好理解，使用相对导入的模块就是为了内部互相的引用资源的，不是为了直接运行的，对于包来说，正确的使用方式还是在顶级模块使用这些包。
十.访问控制
使用 from xyz import * 导入 1.如果模块没有 __all__ ， from xyz import * 只导入非下划线开头的该模块的变量。如果是包，子模块也不 会导入，除非在 __all__ 中设置，或 __init__.py 中导入它们 2.如果模块有 __all__ ， from xyz import * 只导入 __all__ 列表中指定的名称，哪怕这个名词是下划线开头 的，或者是子模块 3.from xyz import * 方式导入，使用简单，但是其副作用是导入大量不需要使用的变量，甚至有可能造成名 称的冲突。而 __all__ 可以控制被导入模块在这种导入方式下能够提供的变量名称，就是为了阻止from xyz import *导入过多的模块变量，从而避免冲突。因此，编写模块时，应该尽量加入 __all__ from module import name1, name2 导入 这种方式的导入是明确的，哪怕是导入子模块，或者导入下划线开头的名称 程序员可以有控制的导入名称和其对应的对象
十一.模块变量的修改
模块对象是同一个，因此模块的变量也是同一个，对模块变量的修改，会影响所有使用者。
除非万不得已，或明确知道自己在做什么，否则不要修改模块的变量。
前面学习过的猴子补丁，也可以通过打补丁的方式，修改模块的变量、类、函数等内容。
#！/usr/bin/env python #_*_conding:utf-8_*_ #@author :yinzhengjie #blog:http://www.cnblogs.com/yinzhengjie print(__name__) PI = 3.14
#！/usr/bin/env python #_*_conding:utf-8_*_ #@author :yinzhengjie #blog:http://www.cnblogs.com/yinzhengjie import test01 as t1 print(t1.PI)
1 #！/usr/bin/env python 2 #_*_conding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie 5 6 import test01 as t1 7 8 print(t1.PI) 9 t1.PI = 3.1415926 10 11 import test02
test01
3.14
3.1415926