Sorting list of URLs by length in Jython

Question

Hi,

I am writing a Jython script to sort a list of URLs.

I have a list that looks like this:

http://www.domain.com/folder1/folder2/|,1
http://www.domain.com/folder1/|,1
http://www.domain.com/folder1/folder2/folder3/|,1
http://www.domain.com/folder1/|,1
http://www.domain.com/folder1/folder2/|,1
http://www.domain.com/folder1/folder2/|,1
http://www.domain.com/folder1/folder2/folder3/|,1

The pipe and the comma separates the path from the amount of files that are under that path. Is it possible some how use Jython to order the URLs by length, so it would end up look like the below list:

http://www.domain.com/folder1/|,1
http://www.domain.com/folder1/|,1
http://www.domain.com/folder1/folder2/|,1
http://www.domain.com/folder1/folder2/|,1
http://www.domain.com/folder1/folder2/|,1
http://www.domain.com/folder1/folder2/folder3/|,1
http://www.domain.com/folder1/folder2/folder3/|,1

Hope you guys get what I mean, any help would be appreciated. Cheers

Answer 1

Wouldn't sorting them take care of this?

Answer 2

Sort-by-length, using a sort function:

urls.sort(lambda a, b: cmp(len(a), len(b)))

For performance, some might prefer the decorate-sort-undecorate pattern:

urllengths= [(len(url), url) for url in urls]
urllengths.sort()
urls= [url for (l, url) in urllengths]

Or as a one-liner:

urls= zip(*sorted((len(url), url) for url in urls))[1]

Answer 3

Until jython catches up to python 2.4, you cannot use the key argument to list.sort():

mylist.sort(key=len)

So, like in the good old days, we have the decorate-sort-undecorate idiom. To sort mylist by item length, we generate a decorated_list of (len(item),item) tuples, sort that, and finally strip the items back:

decorated_list = zip(map(len, mylist), mylist)
decorated_list.sort()
sorted_list = [i[1] for i in decorated_list]