The sys Module
On to module details. As mentioned earlier, the
os modules form the
core of much of Python’s system-related toolset. Let’s
now take a quick, interactive tour through some of the tools in these
two modules, before applying them in bigger examples.
Platforms and Versions
Like most modules,
sys includes both informational
names and functions that take action. For instance, its attributes
give us the name of the underlying operating system the platform code
is running on, the largest possible integer on this machine, and the
version number of the Python interpreter running our code:
sys.platform, sys.maxint, sys.version('win32', 2147483647, '1.5.2 (#0, Apr 13 1999, 10:51:12) [MSC 32 bit (Intel)]') >>> >>>
if sys.platform[:3] == 'win': print 'hello windows'... hello windows
If you have code that must act differently on different machines,
simply test the
sys.platform string as done here;
although most of Python is cross-platform, nonportable tools are
usually wrapped in
if tests like the one here. For
instance, we’ll see later that program launch and low-level
console interaction tools vary per platform today -- simply test
sys.platform to pick the right tool for the
machine your script is running on.
The Module Search Path
sys module also lets us inspect the module
search path both interactively and within a Python program.
sys.path is a list of strings representing the true search path in a running Python interpreter. ...