How to implement my array/collection

[Maddy]

Hi, I have just migrated to C#. I need some advice on the following
problem:
I need to create an object/structure with characteristics A,B and C. A
and B are Integers while C consists of 2 Integers. I need to store
data in these, every 5 sec or so, each value with a DateTime stamp/
index. I will need a method to write the value with the DateTime.
Another method to get the value for a specific DateTime. However, for
getting the value, there might not be a corresponding DateTime index.
In that case, the value closes to that time should be provided. What
is the best method of implementing this? I would require ten instances
of this object at any time. PLease advice.
Thanks
Maddy

[Maddy]

Thanks for the ideas. Few things however-
When I said only 10 objects, I meant the entire object. A,B and C
would have about 400 to 500 values. Would have so many values in
memory slow down the app? Should I save them more often to a file?
Secondly each A, B and C need an individual timestamp.

[Marc Gravell]

On 20 Mar, 02:28, Maddy <[e-mail]:

Thanks for the ideas. Few things however-
When I said only 10 objects, I meant the entire object. A,B and C
would have about 400 to 500 values. Would have so many values in
memory slow down the app? Should I save them more often to a file?
Secondly each A, B and C need an individual timestamp.

OK - can I just double check what you are describing? In terms of a
visualisation, do you mean:

SomeList [~10 of]

"A"s
int, timstamp pair [~500 of]
"B"s
int, timestamp pair [~500 of]
"C"s
int,int,timestamp triple [~500 of]

or do you mean:

SomeList [~10 of]

Items [~500 of]
timestamp, int "A", int "B", {int/int} "C"

- i.e. are A/B/C timstamped separately, or is it each combination of
an A,B & C that is timstamped.

Also 500 is not a big number. I wouldn't worry about memory - but how
often do you need to seach it for a value (by date)? knowing that
might help pick the most suitable structure. If it is infrequent (i.e.
5s, the only timing in your post) then I wouldn't get excited, and
would just use a List search (as already posted). [In any event, keep
the data in timestamp sequence]
If it is more frequent than this, then perhaps a binary search - or if
you know the data is coming in at regular intervals (every 5s) you
could use interpolation of the query value between the start/end
values to find a first guess and then hunt from here.

Let me know how often you search and I'll try to knock an example
together...

Marc

[Marc Gravell]

To be honest, if you are thinking of using disk storage, and the rate
is only every 5-10s, why not just pump everything into a database and
use SQL to do it? It would be a lot simpler, and you wouldn't have to
worry about the difference between in memory and persisted. SQL
Express is free and more than up to this - blus LINQ-to-SQL should be
able to cope with expressions like the one in my early posts.

I still don't really understand the A/B/C mapping...

Marc

[Marc Gravell]

I'll re-read on Tuesday (long weekend) - but in real terms I would
consider "install SQL Express" a very simple option...