Random Find

[Mary Cairns]

Can anyone advise how to find a random 10% of my database for purposes of conducting a survey? I have 9800 records, each with an individual number. I need to select 10% at random.

[Vaughan]

Create an unstored calculation field in your database (I'll call it cRdm but the name is arbitrary)

cRdm = Random

Make sure it's unstored, and the result type is set to number.

Then create this script:

Show all Records

Sort [by field cRdm]

Loop

Exit Loop If [status(CurrentFoundCount) <= (Status(CurrentRecordCount) / 10)]

Omit Record

End Loop

Every time you sort the database it'll sort differently (because the Random calculation will change each time because it's unstored). The loop then omits the unwanted records.

I haven't tested this but it should work.

[BobWeaver]

Rather than omit 90% of the records, why not omit 10% and then do a Show Omitted? Should be quicker.

Show all Records

Sort [by field cRdm]

Loop

Exit Loop If [status(CurrentFoundCount) <= (Status(CurrentRecordCount) *.9)]

Omit Record

End Loop

Show Omitted

[John Caballero]

Wow...both cool suggestions. I'd read this earlier and was wondering how best to go about this.

[Ugo DI LUCA]

I guess without the loop, it will be even quicker.

g_Percent (global number- Enter your percentage here)

cRdm =Random

SetField[g_Percent =Int(Status(CurrentRecordCount)*(g_Percent/100) )+1)]

Show all Records

Sort [by field cRdm]

GoToRecord[by Field Value - g_Percent]

OmitNext[500000-no dialog] *

Put here one of these number of records you won't never have in your file...

[Mary Cairns]

Thanks guys. It works beautifully. You are all angels.