On Fri, Mar 7, 2008 at 2:38 PM, waltbrad <[EMAIL PROTECTED]> wrote: > The script comes from Mark Lutz's Programming Python. It is the > second line of a script that will launch a python program on any > platform. > > import os, sys > pyfile = (sys.platform[:3] == 'win' and 'python.exe') or 'python' > > Okay, run on a win32 machine, pyfile evaluates to python.exe > > That makes sense. Because the first condition is true and 'python.exe' > is true. So the next comparison is 'python.exe' or 'python' Well, > python.exe is true. So that value is returned to pyfile. > > Now. Run this on linux. The first condition evaluates sys.platform[:3] > == 'win' as false. So, the next comparison should be 'False' or > 'python' -- This is because 'and' returns the first false value. > But, again, on linux pyfile evaluates to python.exe > > Where am I going wrong. And when will this statment make pyfile > evaluate to 'python' ? > -- > http://mail.python.org/mailman/listinfo/python-list >
In Python 2.5, this is written: pyfile = 'python.exe' if 'win' in sys.platform else 'python' However, this is a pretty bad way of doing this at all. sys.executable is better. I'm not sure when sys.executable was added but I assume it's more recent than whatever version Lutz used in his book. -- http://mail.python.org/mailman/listinfo/python-list
