Trouble sorting a list of objects by attributes

Miki miki.tebeka at gmail.com
Fri Feb 6 21:56:25 CET 2009


> I've found myself stumped when trying to organize this list of
> objects.  The objects in question are timesheets which i'd like to
> sort by four attributes:
>
> class TimeSheet:
>   department = string
>   engagement = string
>   date = datetime.date
>   stare_hour = datetime.time
>
> My ultimate goal is to have a list of this timesheet objects which are
> first sorted by departments, then within each department block of the
> list, have it organized by projects.  Within each project block i
> finally want them sorted chronologically by date and time.

Python "natural" sort for tuples is doing the right thing for you, for
example:
from operator import attrgetter
from random import randint
class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __repr__(self):
        return "(%s, %s)" % (self.x, self.y)


points = [Point(randint(1, 10), randint(1, 10)) for i in range(10)]
print points
points.sort(key=attrgetter("x", "y"))
print points

Gave me:
[(2, 3), (1, 4), (4, 4), (6, 6), (2, 10), (3, 5), (7, 1), (3, 6), (4,
1), (9, 6)]
[(1, 4), (2, 3), (2, 10), (3, 5), (3, 6), (4, 1), (4, 4), (6, 6), (7,
1), (9, 6)]

Points first sorted by 'x' and then by 'y'.

HTH,
--
Miki <miki.tebeka at gmail.com>
http://pythonwise.blogspot.com



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