[Tutor] iterating through a directory

[Mark Lawrence]

On 09/09/2015 14:32, richard kappler wrote:
> 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.
>

I'm not sure what you're trying to do so maybe 
https://docs.python.org/3/library/collections.html#collections.deque or 
https://docs.python.org/3/library/itertools.html#itertools.cycle

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence