[Tutor] Sorting a List

[Bill Allen]

Corey,

I have a bit of code that use in a CGI that sorts some picture files,
perhaps something like this will work for you.

The file sorting bit:
dir_list = os.listdir("/localhost/html/pics")
dir_list.sort()  #sorts the list of filenames in place

Just in case there is something else useful in the routine I am using, here
is the total code.   It not produces a sorted list of the file names, it
keeps the amount of files in the directory from growing out of control in my
particular Python CGI app.   In this case, I keep only the 5 most recent
files.  The code does not have to look at the file timestamps to do this
because I am using the epoch time at time of the file's creation as the
file's name i.e.  from time import time; new_filename = str(int(time()))
.

file_list = ""
count = 0
dir_list = os.listdir("/localhost/html/pics")
dir_list.sort()
for file in dir_list:
    count = count + 1
    if count < 5:
        pass
    else:
        basename = os.path.basename(file)
        if basename.endswith('.png'):
            file_list = file_list + basename+'\n'
            os.remove("/localhost/html/pics/"+dir_list[0])

--Bill Allen



On Wed, Jan 12, 2011 at 6:56 PM, Corey Richardson <kb1pkl at aim.com> wrote:

> Hello Tutors,
>
> I am generating XML definitions for animations to be used in a
> FIFE-based game. I need to sort the frames of the animations, and I am
> currently using:
> sorted([image for image in os.listdir(path) if image.endswith('.png')])
>
> The final output in the XML is:
>
>        <frame source="walk_0.png"/>
>        <frame source="walk_1.png"/>
>        <frame source="walk_10.png"/>
>        <frame source="walk_11.png"/>
>        <frame source="walk_2.png"/>
>        <frame source="walk_3.png"/>
>        <frame source="walk_4.png"/>
>        <frame source="walk_5.png"/>
>        <frame source="walk_6.png"/>
>        <frame source="walk_7.png"/>
>        <frame source="walk_8.png"/>
>        <frame source="walk_9.png"/>
>
> Having frame 10 and 11 between frame 1 and 2 is not desired behavior;
> how can I sort all of these with walk_10.png and company (this isn't the
> only animation like this) being after walk_9.png? A google search
> doesn't return anything I could use. I tried just using
> [image for image in os.listdir(path) if image.endswith('.png')],
> but that doesn't appear to have any order.
>
> Thanks,
> Corey Richardson
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