I am trying to replace missing values that occur before the first non-null entry in SAS. I have the following data:
StudentID Day TestScore
Student001 0 .
Student001 1 78
Student001 2 89
Student002 3 .
Student002 4 .
Student002 5 .
Student002 6 95
I'd like to modify the data so the null values are replaces with the next available non-null entry:
StudentID Day TestScore
Student001 0 78
Student001 1 78
Student001 2 89
Student002 3 95
Student002 4 95
Student002 5 95
Student002 6 95
data scores;
length StudentID $ 10;
input StudentID $ Day TestScore;
datalines;
Student001 0 .
Student001 1 78
Student001 2 89
Student002 3 .
Student002 4 .
Student002 5 .
Student002 6 95
;
run;
proc sort data = scores;
by descending day;
run;
data scores;
drop addscore;
retain addscore;
set scores;
if testscore ne . then addscore = testscore;
if testscore eq . then testscore = addscore;
run;
proc sort data = scores;
by day;
run;
proc sort data = have;
by id descending day ;
run;
data want;
set have;
by id;
retain last_score;
if first.id then call missing(last_score);
if not missing(score) then last_score = score;
else score = last_score;
run;
proc sort data=want;
by id day;
run;
FYI, this will NOT set the missing values if there are any after the last known score for a given ID. i.e. if you had something like:
Student002 5 95
Student002 6 .
Then only records prior to day 5 for id 002 will get a value of 95. Is that a possible condition for you? If yes, this solution will require a slight modification
You can use a DOW loop to identify the next non-missing score, and a subsequent DOW loop to apply the non-missing score. The DOW approach does not require sorting and maintains the original row order.
data want;
do _n_ = 1 by 1 until (last.id or not missing(score));
set have;
by id;
end;
_score = score;
do _n_ = 1 to _n_;
set have;
score = _score;
output;
end;
drop _score;
run;
In SQL, presuming day ordering, the imputed value can be looked up in a correlated sub-query.
proc sql;
create table want as
select
id, day,
case
when not missing(score) then score
else (select score from have as inner
where inner.id = outer.id
and inner.day > outer.day
and not missing(score)
having inner.day = min(inner.day)
)
end as score
from have as outer;
Related
Suppose I have a data set as below
data have;
input subject$ day$ arm$ var1 var2;
datalines;
100-01 Day1 left 40 30
100-01 Day1 right 35 25
200-01 Day28 left 45 22
200-01 Day28 right 38 15
;
run;
In this data set each subject has two row. But I would like to make one row for each subject. The expected data set is
data want;
input subject$ day$ arm_left$ arm_right$ var1_left var1_right var2_left var2_right;
datalines;
100-01 Day1 left right 40 35 30 25
200-01 Day28 left right 45 38 22 15
;
run;
Any help is appreciated.
This gets you almost there, not the arm portion? Do you actually need that variable (arm_left/arm_right) seems redundant.
data have;
input subject$ day$ arm$ var1 var2;
datalines;
100-01 Day1 left 40 30
100-01 Day1 right 35 25
200-01 Day28 left 45 22
200-01 Day28 right 38 15
;
run;
proc transpose data=have out=long;
by subject day arm;
var var1 var2;
run;
proc transpose data=long out=wide delimiter=_;
by subject day;
id _name_ arm;
var col1;
run;
Another way but may not scale:
data have_left;
set have;
by subject day;
where arm='left';
rename arm = arm_left var1=var1_left var2=var2_left;
run;
data have_right;
set have;
where arm='right';
rename arm = arm_right var1=var1_right var2=var2_right;
run;
data want;
merge have_left have_right;
by subject day;
run;
I have the following data set:
Student TestDayStart TestDayEnd
001 1 5
001 6 10
001 11 15
002 1 4
002 5 9
002 10 14
I would like to make the last 'TestDayEnd' the final value for 'TestDayStart' for each Student.
So the data should look like this:
Student TestDayStart TestDayEnd
001 1 5
001 6 10
001 11 15
001 15 15
002 1 4
002 5 9
002 10 14
002 14 14
I'm not quite sure how I can do this in SAS. Any insight would be appreciated.
After sorting the dataset you can do this within a data step.
proc sort data=have;
by student testdaystart testdayend;
run;
Now you can use the by and retain statements in the data step. The by statement allows you to find the last student, and the retain statement lets you keep the previous value in the dataset.
data want;
set have;
retain last_testdayend;
by student testdaystart testdayend;
output;
last_testdayend = testdayend;
if last.student then do;
if testdaystart ne testdayend then do;
testdaystart = last_testdayend;
testdayend = last_testdayend;
output; * this second output statement creates a new record in the dataset;
end;
end;
drop last_testdayend;
run;
I am trying to transpose a sequence of ranges from an excel file into SAS. The excel file looks something like this:
31 Dec 01Jan 02Jan 03Jan 04Jan
Book id1 23 24 35 43 98
Book id2 3 4 5 4 1
(few blank rows in between)
05Jan 06Jan 07Jan 08Jan 09Jan
Book id1 14 100 30 23 58
Book id2 2 7 3 8 6
(and it repeats..)
My final output should have a first column for the date and then two additional columns for the book Ids:
Date Book id1 Book id2
31 Dec 23 3
01Jan 24 4
02Jan 35 5
03Jan 43 4
04Jan 98 1
05Jan 14 2
06Jan 100 7
07Jan 30 3
08Jan 23 8
09Jan 58 6
In this particular case I am asking for a simpler method to:
Either import and transpose each range of data and replacing the data range with macro variables to separately import and transpose each individual range
Or to import the whole datafile first and then to create a loop that
transposes each range of data
Code I used for a simple import and transpose of a specific data range:
proc import datafile="&input./have.xlsx"
out=want
dbms=xlsx replace;
range="Data$A3:F5" ;
run;
proc transpose data=want
out=want_transposed
name=date;
id A;
run;
Thanks!
A data row that is split over several segments or blocks of rows in an Excel file can be imported raw into SAS and then processed into a categorical form using a DATA Step.
In this example sample data is put into a text file and imported such that the column names are generic VAR-1 ... VAR-n. The generic import is then processed across each row, outputting one SAS data set row per import cell.
The column names in each segment are retained within a temporary array an updated whenever a blank book id is encountered.
* mock data;
filename demo "%sysfunc(pathname(WORK))\demo.txt";
data _null_;
input;
file demo;
put _infile_;
datalines;
., 31Dec, 01Jan, 02Jan, 03Jan, 04Jan
Book_id1, 23 , 24 , 35 , 43 , 98
Book_id2, 3 , 4 , 5 , 4 , 1
., 05Jan, 06Jan, 07Jan, 08Jan, 09Jan
Book_id1, 14 , 100 , 30 , 23 , 58
Book_id2, 2 , 7 , 3 , 8 , 6
run;
* mock import;
proc import replace out=work.haveraw file=demo dbms=csv;
getnames = no;
datarow = 1;
run;
ods listing;
proc print data=haveraw;
run;
When Excel import is be made to look like this:
Obs VAR1 VAR2 VAR3 VAR4 VAR5 VAR6
1 31Dec 01Jan 02Jan 03Jan 04Jan
2 Book_id1 23 24 35 43 98
3 Book_id2 3 4 5 4 1
4
5 05Jan 06Jan 07Jan 08Jan 09Jan
6 Book_id1 14 100 30 23 58
7 Book_id2 2 7 3 8 6
It can be processed in a transposing way, outputting only the name value pairs corresponding to a original cell.
data have (keep=bookid date value);
set haveraw;
array dates(1000) $12 _temporary_ ;
array vars var:;
if missing(var1) then do;
do index = 2 by 1 while (index <= dim(vars));
if not missing(vars(index)) then
dates(index) = put(index-1,z3.) || '_' || vars(index); * adjust as you see fit;
else
dates(index) = '';
end;
end;
else do;
bookid = var1;
do index = 2 by 1 while (index <= dim(vars));
date = dates(index);
value = input(vars(index),??best12.);
output;
end;
end;
run;
I have 1 data set with content description for a school
contents:
num description
content1 math
content2 spanish
content3 geography
content4 chemistry
content5 history
in another data set (students) i have the array content1-content5 and i use a flag to indicate content that have each student.
students
name age content1 content2 content3 content4 content5
BOB 15 1 1 1 1
BRYA 16
CARL 15 1 1
SUE 17 1 1 1
LOU 15 1
if i use a code like this:
data students1;
set students;
array content[5];
format allcontents $100.;
do i=1 to dim(content);
if content[i]=1 then do;
allcontents=cat(vname(content[i]),',',allcontents);
end;
end;
run;
the result is:
name age content1 content2 content3 content4 content5 allcontents
BOB 15 1 1 1 1 content1,content2,content3,content5,
BRYA 16
CARL 15 1 1 content2,content5,
SUE 17 1 1 1 content3,content4,content5,
LOU 15 1 content5
1) i want to use the name of the lookup table (data set contents) to use the name of the content and not the arrays names of content[1-5] in the variable allcontents. how can i do that?
2) and later i want the result by content description, not by student, like this:
description name age
math BOB 15
spanish BOB 15
geography BOB 15
history BOB 15
spanish CARL 15
history CARL 15
spanish SUE 17
chemistry SUE 17
history SUE 17
history LOU 15
is it possible?
thanks.
First, grab the %create_hash() macro from this post.
Use the hash table to look up the values.
data students1;
set students
array content[5];
format num $32. description $16.;
if _n_ = 1 then do;
%create_hash(cnt,num,description,"contents");
end;
do i=1 to 5;
if content[i]=1 then do;
num = vname(content[i]);
rc = cnt.find();
output;
end;
end;
keep description name age;
run;
I find proc transpose suitable. Doing once is enough for question 2) and twice for renaming the variables contents1-5 (hence question 1). The key is the ID statement in proc transpose which automatically rename variables by their corresponding transposed orders.
The code below should give you the desired answers (albeit the name are ordered alphabetically, which may not be the same as your original ordering).
/* original data sets */
data names;
input num $ description $;
cards;
content1 math
content2 spanish
content3 geography
content4 chemistry
content5 history
;run;
data students;
input name $ age content1 content2 content3 content4 content5;
cards;
BOB 15 1 1 1 . 1
BRYA 16 . . . . .
CARL 15 . 1 . . 1
SUE 17 . . 1 1 1
LOU 15 . . . . 1
;run;
/* transpose */
proc sort data=students out=tmp_sorted;
by name age;
run;
proc transpose data=tmp_sorted out=tmp_transposed;
by name age;
run;
/* merge the names of content1-5 */
* If you want to preserve ordering from contents1-contents5
* instead of alphabetical ordering of "description" column
* from a-z, do not drop the "num" column for further use.;
proc sql;
create table tmp_merged as
select B.description, A.name, A.age, B.num, A.COL1
from tmp_transposed as A
left join names as B
on A._NAME_=B.num
order by A.name, B.num;
quit;
/* transpose again */
proc transpose data=tmp_merged(drop=num) out=tmp_renamed(drop=_name_);
by name age;
ID description; *name the transposed variables;
run;
/* answer (1) */
data ans1;
set tmp_renamed;
array content[5] math--history;
format allcontents $100.;
do i=1 to dim(content);
* better use cats (cat does not seem to work);
if content[i]=1 then allcontents=cats(allcontents,',',vname(content[i]));
end;
*kill the leading comma;
allcontents=substr(allcontents,2,99);
run;
/* answer (2) */
data ans2(drop=num col1);
set tmp_merged;
where col1=1;
run;
*cleanup;
proc datasets lib=work nolist;
delete tmp_:;
quit;
In SAS, for the two test datasets below - for every value of "amount" that falls within "y" and "z", I need to extract the corresponding "x". There could be multiple values of "x" that fit into the criteria.
The final result should look something like this:
/*
4 banana eggs
15 .
31 .
7 banana
22 fig
1 eggs
11 coconut
17 date
41 apple
*/
I realize this relies on using indices or binary searches but I can't figure out a workable solution! Any help would appreciated! Thanks!
data test1;
input x $ y z;
datalines;
apple 29 43
banana 2 7
coconut 9 13
date 17 20
eggs 1 5
fig 18 26
;
run;
data test2;
input amount;
datalines;
4
15
31
7
22
1
11
17
41
;
run;
Join the two datasets so amount falls between y and z.
proc sql;
create table join as
select a.amount
,b.*
from test2 a
left join
test1 b
on a.amount between b.y and b.z;
quit;
Sort the result by amount for transpose.
proc sort data=join; by amount; run;
Transpose it.
proc transpose data=join out=trans;
by amount;
var x;
run;
Now you have your fruits each in its own variable named col1, col2, ....
If you want them all in one variable separated by a blank, just concatenate them.
data trans2(keep= amount text);
set trans(drop=_name_);
array v{*} _character_;
text = catx(' ', of v{*});
run;
Here is a possible solution using "old-fashioned" data step code plus PROC TRANSPOSE:
data test1;
input x $ y z;
datalines;
apple 29 43
banana 2 7
coconut 9 13
date 17 20
eggs 1 5
fig 18 26
run;
data test2;
input amount;
datalines;
4
15
31
7
22
1
11
17
41
run;
data want(keep=amount x);
set test2;
found = 0;
do _i_=1 to nobs;
set test1 point=_i_ nobs=nobs;
if y <= amount <= z then do;
found = 1;
output;
end;
end;
if not found then do;
x = ' ';
output;
end;
run;
proc transpose data=want out=want2(drop=_name_);
by amount notsorted;
var x;
run;
Note my results do not match that in your example; amount 31 is an "apple".