, I want to send a survey to our customers based on a random selection, but i'am stuck.
The problem is that a customers can appear within multiple categories (like customerid 1 and 2 in the example below) what can lead to duplicates in the random selection
What i need is a example how to realise a random selection which selects random three customers a category without duplicaties.
I'm using Enterprise Guide 4.3
input example
category 1 | customerid |
1 | |
2 | |
3 | |
4 | |
5 | |
category 2 | customerid |
1 | |
2 | |
8 | |
7 | |
10 |
output example
category 1 | customerid |
1 | |
2 | |
3 | |
category 2 | 8 |
9 | |
7 |
One approach would be:
Assign a pseudo-random number between 0 and 1 (the RANUNI function) to every record.
Sort by customerid and that number (the category will now be in a random order within customerid).
Select the first of each customerid (now have one record per customerid).
Re-sort by category and the random number (the customerids will now be in a random order within category).
Select first 3 in each category.
Doc Muhlbaier
Duke
Thanks for your reply.
I only have one more question; how do I select the first 3 rows by each category?
Harm Klaassen
Harm,
I would usually use a DATA step and a retain statement for that. Something like
DATA want;
SELECT have;
BY category;
RETAIN counter; DROP counter;
IF first.category THEN counter=0;
IF counter <=3 THEN OUTPUT;
RUN;
Doc
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