Ordered dictionary?

[Leif K-Brooks]

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.

[BW Glitch]

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.

A dictionary could be used. When you need to managed the items in order,
what you would do is called dict.keys(), followed by a sort.

I don't know if this helps at all...

--
Glitch

http://andres980.tripod.com/

"That is the law of the jungle. The hunters and the hunted. Scrap or
be scrapped!"
"Animals hunt to SURVIVE!"
"And what do you think war is about?!"
-- Dinobot and Tigatron, "The Law of the Jungle"

[Josiah Carlson]

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?

- Josiah

[John Hunter]

>>>>> "Leif" == Leif K-Brooks <eu*****@ecritt ers.biz> writes:

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

google : python ordered dictionary
click : I'm feeling lucky

JDH

[Jonathan Daugherty]

# 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.

As the other posts on this thread suggest, dictionaries -- by virtue
of their structure -- have no inherently meaningful ordering. You'll
have to either sort the keys (the easy way) or design a wrapper for
the dictionary that maintains a sorted list of the dictionary's
keys and updates it as necessary (the hard way).

--

Jonathan Daugherty
http://www.cprogrammer.org

"It's a book about a Spanish guy called Manual, you should read it."
-- Dilbert

[Paul McGuire]

"Leif K-Brooks" <eu*****@ecritt ers.biz> wrote in message
news:le******** **********@news hog.newsread.co m...

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.

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

-- Paul

[Leif K-Brooks]

Josiah Carlson 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?

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

[BW Glitch]

Leif K-Brooks wrote:

Josiah Carlson 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?

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

That should do. Looks promising, but I think it uses the old style of
extending the dictionary (Not that it's bad) ...

--
Glitch

http://andres980.tripod.com/

One good shot is worth a hundred bad ones!
-- Big Shot (G1)

[Antoon Pardon]

Op 2004-01-22, Paul McGuire schreef <pt***@users.so urceforge.net>:

"Leif K-Brooks" <eu*****@ecritt ers.biz> wrote in message
news:le******** **********@news hog.newsread.co m...

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.

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

[Dragos Chirila]

Hi

Maybe this code will help:

import operator

def filterList(p_li st, p_value):
l_len = len(p_list)
l_temp = map(None, (p_value,)*l_le n, p_list)
l_temp = filter(lambda x: x[1].find(x[0])==0, l_temp)
return map(operator.ge titem, l_temp, (-1,)*len(l_temp) )

phones_dict = {'jansen' : '0000', 'xxx' : '1111', 'jan2' : '2222'}
names_list = filterList(phon es_dict.keys(), 'jan')
phones_list = map(phones_dict .get, names_list)

print phones_list

This extracts from the dictionary the telephone(value s) numbers for
names(keys) starting with 'jan'...

Dragos

Op 2004-01-22, Paul McGuire schreef <pt***@users.so urceforge.net>:

"Leif K-Brooks" <eu*****@ecritt ers.biz> wrote in message
news:le******** **********@news hog.newsread.co m...

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.

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