Sorting a dictionary on Key or Item?

Hi
I'm trying to write a class to wrap the scripting dictionary object

I was trying to make an add method that could add items in a sorted fashion
(or be able to sort after the fact)

can't seem to find any tips on google, just wondering if anyone's tackled
this before?

part of the class so far:
Option Explicit
Private mDict As Scripting.Dictionary
Private Sub Class_Initialize()
Set mDict = New Scripting.Dictionary
End Sub

Private Sub Class_Terminate()
Set mDict = Nothing
End Sub

a non-functioning pseudo code idea for a sorted add
Public Sub Add(ByVal sKeyName As String, ByVal vItem As Variant, ByVal
iSorted As Integer)
Dim lngIndex As Long

Select Case iSorted
Case Is = 0
'sort by key property
'if dict is begun, put item in correct slot
If mDict.Count > 0 Then
For lngIndex = 1 To mDict.Count
'here, I know the item doesn't have a key property but if it
did, I'd do something like this
If sKeyName < mDict.Item(lngIndex).key Then

'here I know the dictionary doestn' have a before: modifier but it it did,
i'd try something like:
mDict.Add sKeyName, vItem, before: mDict.Item (lngIndex)
exit for

End If
Next lngIndex
Else
'just starting
mDict.Add sKeyName, Item 'add first item

End If

Case Is = 1
'sort on item property
'etc
End Select

End Sub

if I can't sort them as I insert them I guess I can sort them after the fact
by creating a temp dict thus:

Keyarray = sourceDict.Keys
SortedArray = SortArray(keyarray)

For i = 0 To ubound(sortedarray) 'Iterate the array
key = SortedArray(i)
item= SourceDict.Item(key)
SortedDict.Add key, item
next

with this scenario sorting on the item may be harder because I can get an
item from a key but I don't see how to get a key from an item

the immediate impetus for the idea was I wanted to make a list of blocknames
and their respective counts
so I was going to use a dictionary, use the blockname for key and count for
item
this works but either i have to sort the blocknames first then put in
dictionary, or sort the dictionary (what I was trying above), or collect the
information from the dictionary and sort it afterwards when I want to read
back the list

I just thought a sortable Add method would save a couple steps

Any thoughts?
Tia
Mark

 

You don't think this is a bit rich for counting block references?

I would use a dynamic array and sort it. This task is so small that
preformance is not an issue.

Of course, if you want to go all the way, read up on balanced binary
trees...

 

well, maybe I'm just dense....
actually, the 'maybe' is superfluous

The only routines I've seen to count block refs do nothing more than count
the direct insertions. If that's all I needed to do, then I guess I
wouldn't need a collection.

as I said this was just the initial impetus to try to sort a collection by
key, there could be other uses imaginable.
For my purposes i need to count blocks but also eventually i need to also
find certain entities meeting search criteria and measure and count them as
well, etc.

so I see a use for this in my situation beyond just counting blocks.

in my present case however, i want to know how many "x" blocks there are
whether they are direct insertions, or occurances embedded in 'y' blocks,
which may have multiple occurances in 'z' blocks, any of which may be
'local' blocks or xrefs.
further I wanted to do this in object dbx since I may have to step through
hundreds of local blocks and multiple external drawings(xrefs) iterating
owner blocks (mspace or blockdefs) looking for embedded blocks, it seemed i
needed a persistant collection object to hold and increment a tally of
blocks.
I don't want to iterate over model space 100 times if I have 100 blocks to
count, i want to iterate once and each block goes into it's cubby hole and
gets counted.

well, it may seem small to you but I've been working on this off and on for
a couple years when I have time - which isn't often - and still don't have
anything functional so i'm obviously a very slow learner.

so I'm trying to understand what you mean by using a dynamic array and
sorting.
do you mean a two dimensional array? one dimension for the block name and
the other for the count?

in lisp i'd use an association list (blockname . count)
or (blockname count)

or do you mean an array of arrays of two members
(array
subarray
subarray
subarray
)
where each sub array is
(array blockname count)
?

off the top of my head it seems like the code logic to handle this using
arrays and haveing to redim everytime would be much more complicated than
being able to call
IncrementCount(collection.item(blockname))
or something like that

it seems like linked lists or hash tables are something similar to
association lists in lisp,maybe that's what you're calling balanced binary
trees
unfortunately my ignorance is only exceeded by my lack of knowlege!

back to the help files...

anyway thanks for the response.
Mark

by the way, fwiw, i was finally able to sort the dictionary on keys by
creating a temp dict and then swapping.
I could do the same for the items but it would be more complex swap
algorithm

I'd also like to try to put keys/items into a dictionary in order in the
first place, (like the collection.add before: syntax) rather than sorting
afterwards but that seemed like it would take more complex code, and sorting
afterwards is almost trivial so I guess it's no big deal.

 

Wayne,
Thanks as always for your invaluable insights
I'll check those links when I get time.
Have a splendiferous day!
Mark

Mark,

I've never worked with blocks so I only have a cursory knowledge of them
based on what I've read on here in passing. This may be why I don't
understand *why* you need your list sorted - you seem to be wanting to
increment a count for each block name but I can't see why the list of names
needs to be in order (or was it the counts that you wanted in order??).

I only wanted to end up with a list alphabetically listed in a final
'printout' or result - so I could quickly locate whatever name I was looking
for at the time

for the sake of gathering information it's unimportant

as you point out there could be many ways to alphabetize the resultant list

 

Hi Mark,
I did an ATP course for AUGI a while back that you may find interesting.
The thrust of the course wasn't data structures, but a good deal of it
revolved around the creation of a List data structure which at one point
evolved into a SortedList structure. This SortedList structure sorts
objects as they are inserted onto the list according to the sort rule(s)
that you set up for the objects being stored. I uploaded a portion of the
class and the accompanying VB files to CF with the title "SortedList Class".

Like I said, the focus of the course wasn't on building a solid data
structure, but along with the excellent links that Wayne provided I think
that you'll have enough ideas about data structures to use them to your
advantage. Let me know if you have any questions!

 

Thanks Bobby,
I'll check it out
Mark

 

dude!



Thank you again for those fantastic links!



That Francesco is one articulate brainiac is he not!?!



And I mean that in the best sense of the word!



~



Mark



&nbsp;



"wivory" &lt;&gt; wrote in message news:...

 

Bobby,
Thank you for that great education
Well written, clear and informative and nice example of implements
I've read about it many times but have n't used
nice to see it in 'real life!'
there's a lot to digest there!

may your way be littered with happiness

 

Thanks Mark, right back at ya!

I've uploaded the previous section of the course to CF titled "Interface
Implementation". The first half of this document describes in detail a much
more common use of interfaces and the mechanics behind creating and using
them. Enjoy <g>