Reading/writing files

[Matt Bergin]

lost wrote:
...
> I need something like this
> 
> for line in a file
> 	print line
> print done

for line in file('afile.txt', 'rb')
     print line
print 'done'

> and for writing, I've tried doing file.write(blah) (blah is a list), but
> it wont write.
> I need to write lists into a file, but i cant.  are there other methods
> for printing to a file, other than file.write?

You need to convert whatever you want to a file to a string first. Take 
a look at the pickle module.

 From the Python tutorial:
----------------
If you have an object x, and a file object f that's been opened for 
writing, the simplest way to pickle the object takes only one line of code:

pickle.dump(x, f)

To unpickle the object again, if f is a file object which has been 
opened for reading:

x = pickle.load(f)

(There are other variants of this, used when pickling many objects or 
when you don't want to write the pickled data to a file; consult the 
complete documentation for pickle in the Library Reference.)
----------------

Or you could do

file.write(':'.join(list))

To join the list with colons (if it is a list of strings), and to read 
it back you could do

list = line.split(':')

> Also, do i need to take into account the \n at the end of a line?

line = line.rstrip() will remove the \n.

-- 
Matt Bergin