[Python] Ordered dictionary?

Leif K-Brooks wrote:
I need to associate a string (key) with an integer (value). A dictionary
would do the job, except for the fact that it must be ordered. I also
need to look up the value for a specific key easily, so a list of tuples
wouldn't work.

How must the dictionary be ordered? Do you need the keys or the values
sorted?

Leif K-Brooks wrote:

Josiah Carlson wrote:

Sorry for not making that clear, I need it sorted by the order of
insertion. Looks like
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/107747 might do
what I want...

Op 2004-01-22, Paul McGuire schreef <ptmcg at users.sourceforge.net>:
"Leif K-Brooks" <eurleif at ecritters.biz> wrote in message
news:leWPb.231$af7.162835 at newshog.newsread.com...
If you really need to access the dictionary in sorted key order, is this so
difficult?

dKeys = d.keys()
dKeys.sort()
for k in dKeys:
# do stuff with k and d[k], such as:
print k, "=", d[k]

Or if you are worried about updates to d between the time of key retrieval
and time of traversal (for instance, if a separate thread were to delete one
of the keyed entries), take a snapshot as a list:

dItems = d.items() # from here on, you are insulated from changes to
dictionary 'd'
dItems.sort() # implicitly sorts by key
dItems.sort( lambda a,b: a[1]-b[1] ) # sorts by value, if you so prefer
for k,v in dItems:
# do stuff with k and v, such as:
print k, "=", v # <-- added benefit here of not re-accessing
the list by key

Well I too sometimes need the keys in a dictionary to be sorted and your
solutions wouldn't help. The problem is the following.

I have a number of key value pairs, like names and telephone numbers.
Just more subject to change. Now I want the telephone numbers of everyone
whose name starts with "jan".

Or I just inserted a name and want to know who is alphabetically next.
Or I want to know who is first or last.

--
Antoon Pardon
--
http://mail.python.org/mailman/listinfo/python-list

Carmine Moleti wrote:

Hi Dragos,


Why you didn't used the string.startswith(...) method?

I wrote this:

d={'carmine':'123456','carmela':'4948399','pippo':'39938303'}
for name,number in d.items():
if name.startswith('car'):
print name,number

This also extract from the dictionay all the (name,number) pairs whose
name starts with a given substring ('car' in the example).

Thanks for your answer

Well I too sometimes need the keys in a dictionary to be sorted and your
solutions wouldn't help. The problem is the following.

I have a number of key value pairs, like names and telephone numbers.
Just more subject to change. Now I want the telephone numbers of everyone
whose name starts with "jan".

Or I just inserted a name and want to know who is alphabetically next.
Or I want to know who is first or last.

Leif K-Brooks wrote:

I need to associate a string (key) with an integer (value). A dictionary
would do the job, except for the fact that it must be ordered. I also
need to look up the value for a specific key easily, so a list of tuples
wouldn't work.