topic Re: Select Consecutive Identical values in SAS Programming

Select Consecutive Identical values

molla — Fri, 07 Apr 2017 20:25:57 GMT

Hii,

am not getting the idea about this.pls help me

OBS SUBJECT FLAG DATE

1 A Y

2 A N

3 B Y

4 B Y

5 B Y

6 C N

7 C Y

8 C Y

9 C Y

10 C Y

11 C N

HOW TO GET THE OBSERVATIONS WITH THREE CONSECUTIVE FLAG ‘Y’ ?

Re: base sas

PaigeMiller — Fri, 07 Apr 2017 20:04:24 GMT

@molla wrote:

Hii,

am not getting the idea about this.pls help me

OBS        SUBJECT               FLAG   DATE

1              A                             Y

2              A                             N

3              B                             Y

4              B                             Y

5              B                             Y

6              C                             N

7              C                             Y

8              C                             Y

9              C                             Y

10           C                             Y

11           C                             N

HOW TO GET THE OBSERVATIONS WITH THREE CONSECUTIVE FLAG ‘Y’ ?

So you want observations 5, 9 and 10. Is that correct?

Here's one solution.

data want;
    set have;
    prev1=lag(flag);
    prev2=lag2(flag);
    if flag='Y' and prev1='Y' and prev2='Y' then output;
run;

Re: base sas

ballardw — Fri, 07 Apr 2017 20:18:14 GMT

Please use a subject that relates to the problem. For example this could be Select Consecutive Identical values.

And please show the actuall desired output. Your request could be considered as 1) keep the record where it and the two previous have the same value for flag 2) select all of the records in a row of 3 or more identical values, which depending on how this is interpretted could lead to multiples of some observations due to overlap of the consecutives. Example: Obs 9 is third Y so output observations 7, 8 and 9. Then Obs 10 is 4th Y so output observations 8, 9 and 10.

Your data tends to imply that the consideration should be within a SUBJECT but that was not stated. Otherwise suppose the data looks like this:

OBS        SUBJECT               FLAG   DATE
1              A                             Y
2              A                             Y                             
3              B                             Y
4              B                             N
5              B                             Y
6              C                             N
7              C                             Y
8              C                             Y
9              C                             Y
10           C                             Y
11           C                             N

Should observation 1, 2 and 3 be output?

Re: Select Consecutive Identical values

Ksharp — Sat, 08 Apr 2017 03:01:39 GMT

data have;
input OBS        SUBJECT    $    FLAG $;
cards;
1              A                             Y
2              A                             N                            
3              B                             Y
4              B                             Y
5              B                             Y
6              C                             N
7              C                             Y
8              C                             Y
9              C                             Y
10           C                             Y
11           C                             N
;
run;
data temp;
 set have;
 if flag=lag(flag) and subject=lag(subject) and
    flag=lag2(flag) and subject=lag2(subject) then output;
keep obs;
run;
data key;
 set temp;
 k=obs;output;
 k=obs-1;output;
 k=obs-2;output;
run;
proc sql;
select *
 from have where obs in
 (select k from key);
quit;