At 03:02 PM 4/11/01 +0000, bas.vangils at home.nl wrote:
>Hi everyone,
>
>I've been toying around with sorting a dictonary _by value_ for the last
>couple
>of days. Using 'seqdict' from the ndict-thiny I found, I do just what I
>want...
>at least, that's what I thought *sigh*.
Q: Can dictionaries be sorted?
A: No. Dictionaries have no concept of ordering of their items, such that
the items can be "re-ordered" in the dictionary by sorting them.
Q: Can I retrieve all of the items in a dictionary and sort them?
A: Yes.
>>> d = some_big_dictionary()
>>> i = d.items()
# sort by value
>>> i.sort(lambda x,y: cmp(x[1],y[1]))
# sort by key
>>> i.sort(lambda x,y: cmp(x[0],y[0]))
Q: I only want to use certain items from the dictionary, and sort those. Can I?
A: Yes. Retrieve those items, then sort as above.
>>> d = some_big_dictionary()
>>> keys = ('one', 'two', 'three', 'four')
>>> items = []
>>> for k in keys:
... items.append( (k, d.get(k)) )
...
# sort by value
>>> items.sort(lambda x,y: cmp(x[1],y[1]))
Q: But I really want to have a magical dictionary that orders its items and
allows me to re-order the items inside the dictionary. Can I have that, please?
A: You must implement such an object yourself, and it's not as easy as you
might think. Before you commit to implementing such an object, ask yourself
if you really need it.
--
Robin Thomas
Engineering
StarMedia Network, Inc.
robin.thomas at starmedia.net
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4