[Tutor] Sorting Dictionary of Dictionary by certain Value

[Bill Campbell]

On Tue, Sep 23, 2008, Bill Campbell wrote:
>On Wed, Sep 24, 2008, John Fouhy wrote:
>>2008/9/24 Joe Python <jopython at gmail.com>:
>>> Hi Pythonistas,
>>>
>>> I have a large dictionary of dictionary (50,000+ keys) which has a structure
>>> as follows:
>>[snip]
>>> I want to sort the dictionary by 'income'
>>> Is there an efficient way to do the same.
>>
>>Note that you cannot sort a dictionary.  The best you can do is build
>>a list containing the dictionary keys in the appropriate order and use
>>the dictionary in combination with that list.
>
>What you can do is create a class for the objects in the top
>level dictionary, and create a __cmp__ method in that class using
>cmp to compare the objects in the dictionary, finally sorting the
>values.
>
>class MyStuff(object):
>    def __init__(self, name, income):
>        self.name = name
>        self.income = int(income)

Whoops

The method below should be def __cmp__

>    def cmp(self, other):
>        return(cmp((-self.income, self.name), -other.income, other.name))
>
>d = dict(
>    key1 = MyStuff('john', 10000),
>    key2 = MyStuff('bill', 20000),
>)
>
>vals = d.values()
>vals.sort()
># vals should be sorted by income in descending order and name.
>
>Bill
>--
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-- 
Bill
-- 
INTERNET:   bill at celestial.com  Bill Campbell; Celestial Software LLC
URL: http://www.celestial.com/  PO Box 820; 6641 E. Mercer Way
Voice:          (206) 236-1676  Mercer Island, WA 98040-0820
Fax:            (206) 232-9186

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