path - Test if executable exists in Python?

Question

In Python, is there a portable and simple way to test if an executable program exists?

By simple I mean something like the which command which would be just perfect. I don't want to search PATH manually or something involving trying to execute it with Popen & al and see if it fails (that's what I'm doing now, but imagine it's launchmissiles)

Answer 1

I know this is an ancient question, but you can use distutils.spawn.find_executable. This has been documented since python 2.4 and has existed since python 1.6.

import distutils.spawn
distutils.spawn.find_executable("notepad.exe")

Also, Python 3.3 now offers shutil.which().