Keep first and last row

[zz]

Hello,

I have the following row of data:

Sub   Date                Phase

01     2016-06-06      Before

01     2016-06-24      During

01     2016-07-01      During

01     2016-08-19      During

01     2016-08-26      After

I need to keep the first and last During to have the data look like this:

Sub   Date                Phase

01     2016-06-06      Before

01     2016-06-24      During

01     2016-08-19      During

01     2016-08-26      After

I tried to use the first. and last variable like below:

DATA JR.SV_021;
SET SV_02;
BY PHASE;
IF first.PHASE THEN OUTPUT;
IF last.PHASE THEN OUTPUT;
run;

but it does not work for me.  I appreciate your help very much in advance!

[Astounding]

A small change should get this to work.  Change the BY statement to:

BY PHASE NOTSORTED;

That will permit your BY statement even though the data are not in order by Phase.

Also note, if your actual data set is larger and might contain more than one SUB value, you may need to use:

BY SUB PHASE NOTSORTED;

Either way, the rest of the program can remain the same.

[zz]

Tried, but somehow, it did not work:(

[ballardw · Accepted solution]

Describe how "doesn't work": Error, unexpected output, no output.

And show the code ran and the log.

[zz]

Hi ballardw, It worked!  I checked and one libref was not correct for input data.  Once that's corrected, it all worked.  Thank you very much!

[zz]

Hi ballardw,

One problem, rows are duplicated, if phase changed in the next row, eg: the first row was duplicated.

[ballardw]

Replace

IF last.PHASE THEN OUTPUT;

with

IF last.PHASE and not (First.Phase) THEN OUTPUT

[Saidurga1]

data durga;

input Sub 2. Date:yymmdd10. Phase $ 24-30;

infile datalines;

cards;

01 2016-06-06 Before

01 2016-06-24 During

01 2016-07-01 During

01 2016-08-19 During

01 2016-08-26 After

;

run;

proc sort data=durga out=class;

by Phase;

run;

data durga_;

set class;

by phase;

if first.Phase=1 or last.phase=1;

run;