https://docs.python.org/3/tutorial/modules.html

1.

当使用import导入后,module里的内容会自动运行

2.

当我们run一个module时,__name__会变成__main__

if __name__ == "__main__": import sys fib(int(sys.argv[1]))

3.module查询

1)首先查询built-in 2)查询sys.path sys.path包含了当前路径,PYTHONPATH 来添加指定路径下的模块,sys.path.append('/ufs/guido/lib/python')

4.caches

To speed up loading modules, Python caches the compiled version of each module in the pycache directory under the name module.version.pyc, where the version encodes the format of the compiled file; it generally contains the Python version number. For example, in CPython release 3.3 the compiled version of spam.py would be cached as pycache/spam.cpython-33.pyc. This naming convention allows compiled modules from different releases and different versions of Python to coexist.

5.packages

假设我们有一个处理声音的package,里面包含了format,effects,filters三个子package,每个package中又有不同的mudule __init__.py将一个directories贬称搞一个package,可以为空,可以做初始化

sound/ Top-level package __init__.py Initialize the sound package formats/ Subpackage for file format conversions __init__.py wavread.py wavwrite.py aiffread.py aiffwrite.py auread.py auwrite.py ... effects/ Subpackage for sound effects __init__.py echo.py surround.py reverse.py ... filters/ Subpackage for filters __init__.py equalizer.py vocoder.py karaoke.py ...

直接导入一个module

import sound.effects.echo sound.effects.echo.echofilter(input, output, delay=0.7, atten=4)

使用from简化

from sound.effects import echo echo.echofilter(input, output, delay=0.7, atten=4)

from也可以导入一个具体的函数,类和变量,但是from..import不能导入package和module

from sound.effects.echo import echofilter echofilter(input, output, delay=0.7, atten=4)

import *

If all is not defined, the statement from sound.effects import * does not import all submodules from the package sound.effects into the current namespace

__all__ = ["echo", "surround", "reverse"]

package内部导入

如果sound.filters.vocoder想要使用sound.effects package中的echomodule,可以使用

from sound.effects import echo

当然也可以使用相对的路径

from . import echo from .. import formats from ..filters import equalizer