## Identifying earliest date across column indicators

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Frequent Contributor
Posts: 138

# Identifying earliest date across column indicators

Hi,

I have a dataset with ID and indicators for each month/year (=1 if person had an event in that month, otherwise =.).

ID    event_200501   event_200502  event_200503.......event_200912

1              1                        1                       1                              .

2               .                        .                        1                              1

I have created an array to identify the earliest month in which a person has an event in each year, like this:

data want;

set have;

array  event2005(12) event_200501--event_200512;

do i=12 to 1;

if event2005(i)=1 then earliest_event_2005=i;

end;

/*Etc for all subsequent years*/

run;

The array runs with no error messages and earliest_event_2005 is created, but it's never actually populated (same with all other years). What I want is the exact same data but with new columns indicating the earliest event each person had in each year.

ID    event_200501   event_200502  event_200503.......event_200912  earliest_event_2005....earliest_event_2009

1              1                        1                       1                              .                           1                                   .

2               .                        .                        1                              1                          3                                   12

Any help is much appreciated.

Accepted Solutions
Solution
‎05-24-2016 01:11 PM
Posts: 1,259

## Re: Identifying earliest date across column indicators

Hi @Walternate,

The issue with your code is that your iterative DO statement is incomplete:

`do i=12 to 1 by -1;`

Of course, ballardw's approach is more elegant.

All Replies
Super User
Posts: 13,583

## Re: Identifying earliest date across column indicators

Try this:

``````data want;
set have;
array  event2005(12) event_200501--event_200512;
earliest_event_2005= whichn(min(of event2005(*)), of event2005(*));
run;
``````
Solution
‎05-24-2016 01:11 PM
Posts: 1,259

## Re: Identifying earliest date across column indicators

Hi @Walternate,

The issue with your code is that your iterative DO statement is incomplete:

`do i=12 to 1 by -1;`

Of course, ballardw's approach is more elegant.

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