python模块----sys模块 （系统相关的参数和函数）

pprint 模块：它给我们提供了一个方法 pprint() 该方法可以用来对打印的数据做简单的格式化

sys模块+pprint模块

• 标准库网址（sys）：https://docs.python.org/3/library/sys.html#module-sys
• 标准库网址（pprint）：https://docs.python.org/3/library/pprint.html#module-pprint

---

• sys.argv

返回一个列表，列表中保存了当前命令的所有参数,argv[0] 为脚本的名称（是否是完整的路径名取决于操作系统）

import sys
import pprint
print(sys.argv)
print(sys.argv[0])
print(sys.argv[1])
print(sys.argv[1:])

• sys.modules

返回一个字典，获取当前程序中引入的所有模块；字典的key是模块的名字，字典的value是模块对象

pprint.pprint(sys.modules)
print(sys.modules.keys())
print(sys.modules.values())
print(sys.modules['os'])

• sys.path

他是一个列表，列表中保存的是模块的搜索路径

pprint.pprint(sys.path)

• sys.platform

表示当前Python运行的平台

print(sys.platform)

• sys.exit()

执行到主程序末尾，解释器自动退出，但是如果需要中途退出程序，可以调用sys.exit函数，带有一个可选的整数参数返回给调用它的程序，表示你可以在主程序中捕获对sys.exit的调用。

sys.exit('程序出现异常，结束！')

---

---

测试

[root@c43i08102.cloud.i09.amtest90 /home]
#cat systest.py
import sys
import pprint
print("------------------------------------")
pprint.pprint(sys.path)
print("------------------------------------")
pprint.pprint(sys.argv)
print("------------------------------------")
pprint.pprint(sys.modules)
print("------------------------------------")
pprint.pprint(sys.platform)
print("------------------------------------")
sys.exit("ERROR!!EXIT")
print("-------test exit--------")
[root@c43i08102.cloud.i09.amtest90 /home]
#python systest.py
------------------------------------
['/home',
 '/usr/local/lib/python2.7/site-packages/setuptools-20.1.1-py2.7.egg',
 '/usr/local/lib/python2.7/site-packages/pip-8.0.3-py2.7.egg',
 '/usr/local/lib/python27.zip',
 '/usr/local/lib/python2.7',
 '/usr/local/lib/python2.7/plat-linux2',
 '/usr/local/lib/python2.7/lib-tk',
 '/usr/local/lib/python2.7/lib-old',
 '/usr/local/lib/python2.7/lib-dynload',
 '/usr/local/lib/python2.7/site-packages']
------------------------------------
['systest.py']
------------------------------------
{'UserDict': <module 'UserDict' from '/usr/local/lib/python2.7/UserDict.pyc'>,
 '__builtin__': <module '__builtin__' (built-in)>,
 '__main__': <module '__main__' from 'systest.py'>,
 '_abcoll': <module '_abcoll' from '/usr/local/lib/python2.7/_abcoll.pyc'>,
 '_codecs': <module '_codecs' (built-in)>,
 '_locale': <module '_locale' from '/usr/local/lib/python2.7/lib-dynload/_locale.so'>,
 '_sre': <module '_sre' (built-in)>,
 '_sysconfigdata': <module '_sysconfigdata' from '/usr/local/lib/python2.7/_sysconfigdata.pyc'>,
 '_warnings': <module '_warnings' (built-in)>,
 '_weakref': <module '_weakref' (built-in)>,
 '_weakrefset': <module '_weakrefset' from '/usr/local/lib/python2.7/_weakrefset.pyc'>,
 'abc': <module 'abc' from '/usr/local/lib/python2.7/abc.pyc'>,
 'cStringIO': <module 'cStringIO' from '/usr/local/lib/python2.7/lib-dynload/cStringIO.so'>,
 'codecs': <module 'codecs' from '/usr/local/lib/python2.7/codecs.pyc'>,
 'copy_reg': <module 'copy_reg' from '/usr/local/lib/python2.7/copy_reg.pyc'>,
 'encodings': <module 'encodings' from '/usr/local/lib/python2.7/encodings/__init__.pyc'>,
 'encodings.__builtin__': None,
 'encodings.aliases': <module 'encodings.aliases' from '/usr/local/lib/python2.7/encodings/aliases.pyc'>,
 'encodings.codecs': None,
 'encodings.encodings': None,
 'encodings.utf_8': <module 'encodings.utf_8' from '/usr/local/lib/python2.7/encodings/utf_8.pyc'>,
 'errno': <module 'errno' (built-in)>,
 'exceptions': <module 'exceptions' (built-in)>,
 'genericpath': <module 'genericpath' from '/usr/local/lib/python2.7/genericpath.pyc'>,
 'linecache': <module 'linecache' from '/usr/local/lib/python2.7/linecache.pyc'>,
 'os': <module 'os' from '/usr/local/lib/python2.7/os.pyc'>,
 'os.path': <module 'posixpath' from '/usr/local/lib/python2.7/posixpath.pyc'>,
 'posix': <module 'posix' (built-in)>,
 'posixpath': <module 'posixpath' from '/usr/local/lib/python2.7/posixpath.pyc'>,
 'pprint': <module 'pprint' from '/usr/local/lib/python2.7/pprint.pyc'>,
 're': <module 're' from '/usr/local/lib/python2.7/re.pyc'>,
 'signal': <module 'signal' (built-in)>,
 'site': <module 'site' from '/usr/local/lib/python2.7/site.pyc'>,
 'sre_compile': <module 'sre_compile' from '/usr/local/lib/python2.7/sre_compile.pyc'>,
 'sre_constants': <module 'sre_constants' from '/usr/local/lib/python2.7/sre_constants.pyc'>,
 'sre_parse': <module 'sre_parse' from '/usr/local/lib/python2.7/sre_parse.pyc'>,
 'stat': <module 'stat' from '/usr/local/lib/python2.7/stat.pyc'>,
 'sys': <module 'sys' (built-in)>,
 'sysconfig': <module 'sysconfig' from '/usr/local/lib/python2.7/sysconfig.pyc'>,
 'traceback': <module 'traceback' from '/usr/local/lib/python2.7/traceback.pyc'>,
 'types': <module 'types' from '/usr/local/lib/python2.7/types.pyc'>,
 'warnings': <module 'warnings' from '/usr/local/lib/python2.7/warnings.pyc'>,
 'zipimport': <module 'zipimport' (built-in)>}
------------------------------------
'linux2'
------------------------------------
ERROR!!EXIT