Re: Using the random function

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To have a random number, use Rnd().

In a query, that will be 'optimized' as being a 'constant', meaning it is
recognize to NOT depend on any field of any tables. So, it will be computed
only ONCE, at the beginning of the query execution. To have it executed for
each row, use a numeric field as argument: Rnd( fieldName )

To have a pick without duplicated values, that depends on how many out of
many you pick, and if the picking is ordered, or not. As example, to pick
two cards, in order, in a play a 52 cards won't use the same strategy than
to pick the all the 52 cards, in order. In the last case, someone can take a
sequence of 52 random numbers and then, find their ranks: get the order of
picking each card accordingly to the rank value of each random number:

Card RandomValue Rank
1-Spade 0.000456 3
2-Spade 0.956958 51
....

so, the Ace of spade will the be third card to be picked, while the two of
space will be the before last one of the stack. The rank is computed from
the randomValue values. The rank of 3 assumes that 0.000456 is the third
smallest random value in the set of 52 random values we got. The rank of 51
assumes that 0.956958 is the second highest random value in the set.



Hoping it may help,
Vanderghast, Access MVP



"Aaron" <aaronsan@xxxxxxx> wrote in message
news:1192544017.736405.263640@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi all...first post in about a year, but you all (on other access ngs)
were so helpful last time I couldn't imagine not asking for help
again!

I am trying to write a query that populates several lists (of certain
lengths, which I already have produced) with one field that is
randomly generated from a larger list of a very similar type.
Basically, I am predicting future data based on several years of
historical data. I would like the field in question, call it
"Response", to be a random selection from the "Response" field of
those multiple years (in one table).

I am populating a list of about 2,000, from a list of about 16,000, so
I think I can choose random numbers WITH replacement (makes it easier,
right?), but if you would still recommend choosing without
replacement, please let me know how to do that.

At any rate, I want to randomly choose one of the 16,000 Responses
(they are integers) as the entry for each "Response" in the new,
predicted, list of 2,000.

My preferred way of solving this would be to use a query in design
mode. I was hoping I could do this without coding.

For the table names, call the list of 2,000 "2006", and the list of
16,000 "Allyears".

Thank you!

-Aaron



.

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