How to temporarily modify sys.path in Python?

Question

In one of my testing scripts in Python I use this pattern several times:

sys.path.insert(0, "somedir") mod =  __import__(mymod) sys.path.pop(0) 

Is there a more concise way to temporarily modify the search path?

Answer 1

You could use a simple context manager:

import sys  class add_path():     def __init__(self, path):         self.path = path      def __enter__(self):         sys.path.insert(0, self.path)      def __exit__(self, exc_type, exc_value, traceback):         try:             sys.path.remove(self.path)         except ValueError:             pass 

Then to import a module you can do:

with add_path('/path/to/dir'):     mod = __import__('mymodule') 

On exit from the body of the with statement sys.path will be restored to the original state. If you only use the module within that block you might also want to delete its reference from sys.modules:

del sys.modules['mymodule']