Sorted and reversed on huge dict ?

[vd12005 at yahoo.fr]

Hello,

i would like to sort(ed) and reverse(d) the result of many huge
dictionaries (a single dictionary will contain ~ 150000 entries). Keys
are words, values are count (integer).

i'm wondering if i can have a 10s of these in memory, or if i should
proceed one after the other.

but moreover i'm interested in saving theses as values, keys sorted and
reversed (ie most frequent first), i can do it with sort from unix
command but i wonder how i should do it with python to be memory
friendly.

can it be done by using :

from itertools import izip
pairs = izip(d.itervalues(), d.iterkeys())
for v, k in reversed(sorted(pairs)):
    print k, v

or will it be the same as building the whole list ?