[Tutor] iterating through a directory

[richard kappler]

Yes, many questions today. I'm working on a data feed script that feeds
'events' into our test environment. In production, we monitor a camera that
captures an image as product passes by, gathers information such as
barcodes and package ID from the image, and then sends out the data as a
line of xml to one place for further processing and sends the image to
another place for storage. Here is where our software takes over, receiving
the xml data and images from vendor equipment. Our software then processes
the xml data and allows retrieval of specific images associated with each
line of xml data. Our test environment must simulate the feed from the
vendor equipment, so I'm writing a script that feeds the xml from an actual
log to one place for processing, and pulls images from a pool of 20, which
we recycle, to associate with each event and sends them to another dir for
saving and searching.

 As my script iterates through each line of xml data (discussed yesterday)
to simulate the feed from the vendor camera equipment, it parses ID
information about the event then sends the line of data on. As it does so,
it needs to pull the next image in line from the image pool directory,
rename it, send it to a different directory for saving. I'm pretty solid on
all of this except iterating through the image pool. My idea is to just
keep looping through the image pool, as each line of xmldata is parsed, the
next image in line gets pulled out, renamed with the identifying
information from the xml data, and both are sent on to different places.

I only have one idea for doing this iterating through the image pool, and
frankly I think the idea is pretty weak. The only thing I can come up with
is to change the name of each image in the pool from something
like 0219PS01CT1_20111129_000004_00044979.jpg to 1.jpg, 2.jpg, 3.jpg etc.,
then doing something like:

i = 0

here begins my for line in file loop:
    if i == 20:
        i = 1
    else:
        i += 1
    do stuff with the xml file including get ID info
    rename i.jpg to IDinfo.jpg
    send it all on

That seems pretty barbaric, any thoughts on where to look for better ideas?
I'm presuming there are modules out there that I am unaware of or
capabilities I am unaware of in modules I do know a little about that I am
missing.

-- 

All internal models of the world are approximate. ~ Sebastian Thrun