Introducing the sys Module

Introducing the sys Modeule

Platforms and Versions

C:\...\PP4E\System> python
>>> import sys
>>> sys.platform, sys.maxsize, sys.version
('win32', 2147483647, '3.1.1 (r311:74483, Aug 17 2009, 17:02:12) ...more deleted...')

>>> if sys.platform[:3] == 'win': print('hello windows')
...
hello windows

 

The Module Search Path

>>> sys.path
['', 'C:\\PP4thEd\\Examples', ...plus standard library paths deleted... ]

>>> sys.path.append(r'C:\mydir')
>>> sys.path
['', 'C:\\PP4thEd\\Examples', ...more deleted..., 'C:\\mydir'] 

The Loaded Modules Table

>>> sys.modules
{'reprlib': <module 'reprlib' from 'c:\python31\lib\reprlib.py'>, ...more deleted...

>>> list(sys.modules.keys())
 ['reprlib', 'heapq', '__future__', 'sre_compile', '_collections', 'locale', '_sre',
'functools', 'encodings', 'site', 'operator', 'io', '__main__', ...more deleted... ]

>>> sys
<module 'sys' (built-in)>
>>> sys.modules['sys']
<module 'sys' (built-in)>

Exception Details

>>> import traceback, sys
>>> def grail(x):
...     raise TypeError('already got one')
...
>>> try:
...     grail('arthur')
... except:
...     exc_info = sys.exc_info()
...     print(exc_info[0])
...     print(exc_info[1])
...     traceback.print_tb(exc_info[2])
...
<class 'TypeError'>
already got one
  File "<stdin>", line 2, in <module>
  File "<stdin>", line 2, in grail