python (read file contents line by line)

sorry but i do not have any prior knowledge of python (was asked to do this though)

so can explain what you have written?
and also can provide the whole program for me, if possible? :x

thank you so much

it first checks if the file exists at all (os.path.exists).
afterwards it opens the file readonly.
now we iterate over all lines (input)
finally it prints the line with removed trailing whitespaces.

actually, that the whole program.

put the following two lines into the head and you are ready to go:
#!/usr/bin/env python
import os

How do i know the python is running??

What do you mean?

you run the script either with ./script.py
or python script.py on commandline

and as unlikely as it seems, these scripts are complete python scripts :X

quick 500 points here it seems, tpoly, you might try reading the documentation that comes with python.. the tutorials are incredibly comprehensive..

You should always close the open file after the processing. In other words, there should be input.close() at the end of the accepted solution. When using try/except, you should also close the file. From Python 2.5, you can also use the new "with" construct. See the standard documentation of 3.9 File Objects http://docs.python.org/lib/bltin-file-objects.html

Citation:

close(        )
    Close the file. A closed file cannot be read or written any more. Any operation which requires that the file be open will raise a ValueError after the file has been closed. Calling close() more than once is allowed.

    As of Python 2.5, you can avoid having to call this method explicitly if you use the with statement. For example, the following code will automatically close f when the with block is exited:

    from __future__ import with_statement

    with open("hello.txt") as f:
        for line in f:
            print line

    In older versions of Python, you would have needed to do this to get the same effect:

    f = open("hello.txt")
    try:
        for line in f:
            print line
    finally:
        f.close()

pepr,

I am very, very new at python (and I am struggling with it, "they" said it was like Pascal, but I have yet to see any similarity).

I was curious about the future statement. At first it seemed odd, like declare something that will exist in the future" but obviously this new "with" statement already exists. Why the "future" declaration? Is it just not "classified" yet. Will this declaration have to be changed in the future, once it is, or what?

Thanks for the discussion!

I found this, it explains it fairly well:
http://docs.python.org/lib/module-future.html

The __future__ is a module that--when used explicitly--allows you to use the features that are not the part of the "mainstream python kernel" (sorry for my English). Think about it as about preview or preliminary versions of the code.

See the end of the "7.5 The with statement" (http://docs.python.org/ref/with.html) documentation. It says (citation):

  "Note: In Python 2.5, the with statement is only allowed when the with_statement feature
    has been enabled. It will always be enabled in Python 2.6. This __future__ import statement can
    be used to enable the feature:

    from __future__ import with_statement"

The __future__ is a Python module written in Python. You can look inside your .../python/Lib/__future__.py.  You can see there that the feature is enabled by setting a compiler flag.