[Tutor] Flatten a list in tuples and remove doubles

[Francesco Loffredo]

Il 19/07/2012 19:33, PyProg PyProg ha scritto:
> Hi all,
>
> I would get a new list as:
>
> [(0, '3eA', 'Dupont', 'Juliette', '11.0/10.0', '4.0/5.0', '17.5/30.0',
> '3.0/5.0', '4.5/10.0', '35.5/60.0'), (1, '3eA', 'Pop', 'Iggy',
> '12.0/10.0', '3.5/5.0', '11.5/30.0', '4.0/5.0', '5.5/10.0',
> '7.5/10.0', '40.5/60.0')]
>
> ... from this one:
>
> [(0, '3eA', 'Dupont', 'Juliette', 0, 11.0, 10.0), (0, '3eA', 'Dupont',
> 'Juliette', 1, 4.0, 5.0), (0, '3eA', 'Dupont', 'Juliette', 2, 17.5,
> 30.0), (0, '3eA', 'Dupont', 'Juliette', 3, 3.0, 5.0), (0, '3eA',
> 'Dupont', 'Juliette', 4, 4.5, 10.0), (0, '3eA', 'Dupont', 'Juliette',
> 5, 35.5, 60.0), (1, '3eA', 'Pop', 'Iggy', 0, 12.0, 10.0), (1, '3eA',
> 'Pop', 'Iggy', 1, 3.5, 5.0), (1, '3eA', 'Pop', 'Iggy', 2, 11.5, 30.0),
> (1, '3eA', 'Pop', 'Iggy', 3, 4.0, 5.0), (1, '3eA', 'Pop', 'Iggy', 4,
> 5.5, 10.0), (1, '3eA', 'Pop', 'Iggy', 5, 40.5, 60.0)]
>
> How to make that ? I'm looking for but for now I can't do it.
>
> Thanks in advance.
>
> a+
>
I had to study carefully your present and desired lists, and I 
understood what follows (please, next time explain !):
- each 7-tuple in your present list is a record for some measure 
relative to a person. Its fields are as follows:
     - field 0: code (I think you want that in growing order)
     - field 1: group code (could be a class or a group to which both of 
your example persons belong)
     - fields 2, 3: surname and name of the person
     - field 4: progressive number of the measure (these are in order 
already, but I think you want to enforce this) that you want to exclude 
from the output list while keeping the order
     - field 5, 6: numerator and denominator of a ratio that is the 
measure. you want the ratio to be written as a single string: "%s/%s" % 
field5, field6

Taking for granted this structure and my educated guesses about what you 
didn't tell us, here's my solution:

def flatten(inlist)
     """
       takes PyProg PyProg's current list and returns his/her desired one,
       given my guesses about the structure of inlist and the desired 
result.
     """
     tempdict = {}
     for item in inlist:
         if len(item) != 7:
             print "Item errato: \n", item
         id = tuple(item[:4])
         progr = item[4]
         payload = "%s/%s" % item[5:]
         if id in tempdict:
            tempdict[id].extend([(progr, payload)])
         else:
            tempdict[id] = [(progr, payload)]
     for item in tempdict:
         tempdict[item].sort() # so we set payloads in progressive 
order, if they aren't already
     # print "Temporary Dict: ", tempdict
     tmplist2 = []
     for item in tempdict:
         templist = []
         templist.extend(item)
         templist.extend(tempdict[item])
         tmplist2.append(tuple(templist))
     tmplist2.sort()# so we set IDs in order
     # print "Temporary List: ", tmplist2
     outlist = []
     for item in tmplist2:
         templist = []
         if isinstance(item, tuple):
            for subitem in item:
                if isinstance(subitem, tuple):
                   templist.append(subitem[1])
                else:
                   templist.append(subitem)
            outlist.append(tuple(templist))
         else:
            outlist.append(item)
     # print "\nOutput List: ", outlist
     return outlist