__file__

[7stud]

Hi,

I'm having trouble understanding what the definition of __file__ is.
With this program:

------
#data.py:

def show():
    print __file__

if __name__ == "__main__":
    show()
-------

if I run data.py with the prompt pointing to the directory that
contains data.py, then __file__ produces a filename:

data.py

If I run data.py with the prompt pointing to a different directory,
then file produces what I entered on the command line, e.g.:

./2testing/dir1/data.py


If I import the data module into another python program, e.g.:

-------
#test1.py:

from data import show
show()
------

and test1.py is in the same directory as data.py, __file__ produces an
absolute path to the data module:

/Users/me/2testing/dir1/data.pyc

If test1.py is in a different directory than data.py, __file__
produces the path used in sys.path.append(), e.g.:

----
import sys
sys.path.append("./2testing/dir1")

import data
data.show()
---output:------
./2testing/dir1/data.pyc

====or======

import sys
sys.path.append("/Users/me/2testing/dir1")

import data
data.show()
---output:-------
/Users/me/2testing/dir1/data.pyc


And some modules have __file__ in their __dict__ and some don't:

-------
import sys, pprint, data

pprint.pprint(data.__dict__)
print
print "*******"
print
pprint.pprint(sys.__dict__)