How to output the running path instead of the location path?

Question

I have the following:

% more a.py 
import os
os.system('pwd')

% python a.py 
/Users/yl/test/f

% cd ..

% python ./f/a.py 
/Users/yl/test

Basically I want the last output to be "/Users/yl/test/f", which is the path where the script is located (not where python was invoked). Have played around but didn't find a good solution. Thanks for any suggestions!

Answer 1

import os
app_dir = os.path.dirname(__file__)
print(app_dir)

Answer 2

import os
print (os.path.dirname(os.path.abspath(__file__)))