Is it possible to sort a dictionary?

[Carel Fellinger]

Alex Martelli <aleaxit at yahoo.com> wrote:

> Fine!  Even faster & simpler:

Simpler yes, but faster? Are you sure?  Lately I tested something
similar and was surprised when I found the dict.items function to be
soo slow that going through the whole dict indexing each entry
one by one was faster.

So let me benchmark again ( and please be gently when you tell me
were I fucked up this time :)


The result were with python 1.5.2:

   tested t_items: 4.76
   tested t_keys:  3.9

and with python 2.0 an even more dramatic advantage for dict.keys:

   tested t_items: 4.6
   tested t_keys:  2.72

And the code used was:

import time

dict = {}
for i in range(1000):
    dict[i] = i

def test(f):
    start = time.clock()
    for i in range(1000):
        f()
    return time.clock() - start


def t_items(dict=dict):
    items = dict.items()
    items.sort()
    for key, value in items:
        v = value

def t_keys(dict=dict):
    keys = dict.keys()
    keys.sort()
    for key in keys:
        v = dict[key]

print 'tested t_items:', test(t_items)
print 'tested t_keys: ', test(t_keys)


-- 
groetjes, carel