Creating a function for a directory

[Rick Johnson]

On Monday, November 11, 2013 4:26:46 PM UTC-6, Matt wrote:

> So I want to take the file, "desktop/test.txt" and write
> it to "desktop/newfolder/test.txt". I tried the below
> script, and it gave me: "IOError: [Errno 2] No such file
> or directory: 'desktop/%s.txt'". Any suggestions would be
> great.
>
> def firstdev(file):
> 	in_file = open("desktop/%s.txt") % file
> 	indata = in_file.read()
> 	out_file = open("desktop/newfolder/%s.txt", 'w') % file
> 	out_file.write(indata)
> 	out_file.close()
> 	in_file.close()
> firstdev("test")

1. i believe win32 file paths require a qualifying volume
letter.

2. Never, ever, *EVER* write data to disc before confirming
the paths your passing are pointing to the location you
intended to write the data. Use os.path.exists(path) to test
your paths BEFORE trying to write data.

3. Be sure your variables names are both "self documenting"
and "non clobbering". psst: "file" is a builtin! Using
"filename" would be a far wiser choice for a variable
containing a filename. When i see "file", i think of a "file
object"

4. When dealing with files you must be sure that exceptions
are handled cleanly. You don't want open file objects
floating aimlessly around in memory because your naive code
blew chunks.

5. Remember, you cannot write a file into a directory that
does not exist.

6 For OS compatibility always use os.path.join() to join
path parts into a whole. This method will insert the proper
separator for you depending on the OS.