Python入门教程 内建模块

常用内建模块

os模块：创建管理进程，平台访问内容。

In : import os
In : os.getcwd()
Out: '/Users/dongweiming/avalon'
In : os.chdir('..')
In : os.getcwd()
Out: '/Users/dongweiming'
In : os.getenv('SHELL')
Out: '/bin/zsh'
In : os.environ.get('SHELL')
Out: '/bin/zsh'
In : os.listdir('migrations')
Out[]:
['script.py.mako',
 'env.py',
 'alembic.ini',
 'versions',
 '__pycache__',
 'README']
In : os.walk('dir1')
Out: <generator object walk at 0x107a078e0>
In : list(os.walk('dir1'))
Out: [('dir1', ['dir3'], []), ('dir1/dir3', [], [])]

os.path模块
In : p = '/home/dongwm/a.txt'
In : os.path.basename(p) #获取指定文件路径的文件名字
Out: 'a.txt'
In : os.path.dirname(p) #获取文件路径的目录名字
Out: '/home/dongwm'
In : os.path.exists(p)  #判断文件或目录是否存在
Out: False
In : os.path.exists('/Users/dongweiming/avalon')
Out: True
In : os.path.isdir(p)  #判断指定路径是否是目录
Out: False
In : os.path.isdir('/Users/dongweiming')
Out: True
In : os.path.isfile(p)  #
Out: False
#
In : os.path.join('/Users', 'dongweiming', 'avalon/app.py'
Out: '/Users/dongweiming/avalon/app.py'
In : os.path.split(p)  #路径拆分
Out: ('/home/dongwm', 'a.tpxt')
In : os.path.splitext(p)  #获取路径
Out: ('/home/dongwm/a', '.txt')

sys模块

In : sys.platform  #
Out: 'darwin'
In : sys.version  #
Out: '3.6.4 (default, Feb 28 2018, 12:22:57) \n[GCC 4.2.1 Compatible Apple LLVM
9.0.0 (clang-900.0.39.2)]'
In : sys.version_info  #
Out: sys.version_info(major=3, minor=6, micro=4, releaselevel='final', serial=0)
In : sys.path[0]  #
Out: '/Users/dongweiming/avalon/venv/lib/python3.6/site-packages'
In : sys.modules.get('xml')  #
Out: <module 'xml' from '/usr/local/Cellar/python3/3.6.4_2/Frameworks/Python.framework/
Versions/3.6/lib/python3.6/xml/__init__.py'>