Python - Sorting lists of numbers

Question

Just learning Python and got on to the subject of sorting lists. Two types of algorithms were shown: insertion and selection. So, I had an idea and created this:

def DiffSort(lst):
    lstDiff = [None] * len(lst)
    i = 0

    while i < len(lst):
        lstDiff[i] = lst[i] - lst[i-1] if i != 0 else lst[0]

        if lstDiff[i] < 0:
            sbj, tmp = lst[i], lstDiff[i]

            while tmp < 0:
                i -= 1
                tmp += lstDiff[i]
                lst[i+1] = lst[i]

            lst[i] = sbj
        else:
            i += 1

lst = [13,25,18,122,32,1,0.78,25,85,1,32,56,0.55,0.6,17]
print(lst)

DiffSort(lst)

print(lst)

Any good? Is there a similar method out there already?

clever, but i think this is just insertion sort, with the downside that it won't work on arbitrary comparables (e.g. strings, tuples, etc). so it won't outdo timsort, sorry :) — Eevee
– Eevee, Commented Feb 24, 2013 at 22:43
Are you looking for the best way to normally sort a list in Python, or are you interested in the theory of sorting algorithms? — Junuxx
– Junuxx, Commented Feb 24, 2013 at 22:44
He's obviously interested on sorting algorithms... and everyone keep answering as if he just asked how to sort a list xD Anyway, OnT: the lstDiff list seems superfluous, you are only using the current index (which could be replaced by a simple variable). Also, agree with Eevee and that it seems like insertion sort using diff instead of conditionals. — asermax
– asermax, Commented Feb 24, 2013 at 22:52
Cheers for the feedback, working my way through an introduction to Python. Just seeing if I was on to something there... lol. — Chadda Wikz
– Chadda Wikz, Commented Feb 24, 2013 at 23:15

Stjepan Bakrac · Accepted Answer · 2013-02-24 22:49:30Z

1

list.sort() if you want to sort a list in-place.

sorted(list) if you want to return a sorted copy of the list.

The second option works with any iterable type, whereas the first is list-exclusive (although some other types may have the same or a similar function defined as well, but you can generally not expect that).

Since you seem to care about the algorithmic part of it, this may be of interest to you: http://svn.python.org/projects/python/trunk/Objects/listsort.txt

answered Feb 24, 2013 at 22:49

Stjepan Bakrac

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Chadda Wikz Over a year ago

Cheers, looks interesting.

Michael Scott Asato Cuthbert · Accepted Answer · 2013-02-24 22:39:15Z

0

Isn't lst.sort() good enough? It's bound to be much faster than a Python solution that has to run in O(n^2) time.

answered Feb 24, 2013 at 22:39

Michael Scott Asato Cuthbert

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