lists.sort() with cmp

[merlem]

What have you tried?

I have tried to get a hint about how to build up a working code - as I had no idea how it should look like. All the things in the SortingHowTo give no (for me understandable) answer to that.

I mean, it's easy to say that

Monday = 'Monday'
Tuesday = 'Tuesday'
Wednesday = 'Wednesday'
Thursday = 'Thursday'
Friday = 'Friday'
Saturday = 'Saturday'
Sunday = 'Sunday'

list1 = [Wednesday, Tuesday, Saturday, Monday, Sunday]
list2 = [Monday, Tuesday, Friday, Wednesday]
list3 = [Sunday, Saturday, Sunday]
list4 = [Friday, Tuesday, Thursday]

list1.sort()
list2.sort()
list3.sort()
list4.sort()

print list1
print list2
print list3
print list4

only give the 'correct' result for list3 - and that's kind of 'accidentally' as in the case of Saturday and Sunday, the alphabetic order is the 'correct' one.

Your problem is defining what is a rather arbitrary sort order between some strings.

And it becomes even much more 'arbitrary' when I leave the weekday example and go to what I wish, yes. But your code is exactly what I've been looking for, as far as I can say for the moment. I will try and see whether I can make my code working in that way.

My own approach was going to something like

def sortdays(day1, day2):
    if day1 == Monday and day2 == Tuesday:
        return -1
    elif day1 == Monday and day2 == Monday:
        return 0
    elif day1 == Tuesday and day2 == Monday:
        return 1
    elif day1 == Tuesday and day2 == Tuesday:
        return 0
    # and so on

but I had the notion (is that the right term?) that this probably is not the most efficient solution...

Then I came up with using a list, maybe like:

def sortdays(day1, day2):
    dayslist = [Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday]
    if dayslist.index(day1) < dayslist.index(day2):
        return -1
    elif if dayslist.index(day1) == dayslist.index(day2):
        return 0
    else:
        return 1

But it seems not necessary that the results are only -1, 0 and 1? The subtraction will give results from -6 to 6?