I want to create a column in my dataset that calculates the sum of the current row and next row for another field. There are several groups within the data, and I only want to take the sum of the next row if the next row is part of the current group. If a row is the last record for that group I want to fill with a null value.
I'm referencing reading next observation's value in current observation, but still can't figure out how to obtain the solution I need.
For example:
data have;
input Group ID Salary;
cards;
10 1 1
10 2 2
10 3 2
10 4 1
11 1 2
11 2 2
11 3 1
11 4 1
;
run;
The result I want to obtain here is this:
data want;
input Group ID Salary Sum;
cards;
10 1 1 3
10 2 2 4
10 3 2 3
10 4 1 .
11 1 2 4
11 2 2 3
11 3 1 2
11 4 1 .
;
run;
Similar to Tom's answer, but using a 'look-ahead' merge (without a by statement, and firstobs=2) :
data want ;
merge have
have (firstobs=2
keep=Group Salary
rename=(Group=NextGroup Salary=NextSalary)) ;
if Group = NextGroup then sum = sum(Salary,NextSalary) ;
drop Next: ;
run ;
Use BY group processing and a second SET statement that skips the first observation.
data want ;
set have end=eof;
by group ;
if not eof then set have (keep=Salary rename=(Salary=Sum) firstobs=2);
if last.group then Sum=.;
else sum=sum(sum,salary);
run;
I found a solution using proc expand that produced what I needed:
proc sort data = have;
by Group ID;
run;
proc expand data=have out=want method=none;
by Group;
convert Salary = Next_Sal / transformout=(lead 1);
run;
data want(keep=Group ID Salary Sum);
set want;
Sum = Salary + Next_Sal;
run;
Related
Hello so this is a sample of my data (There is an additional column of LBCAT =URINALYSIS for those panel of tests)
I've been asked to only include the panel of tests where LBNRIND is populated for any of those tests and the rest to be removed. Some subjects have multiple test results at different visit timepoints and others only have 1.I can't utilise a simple where LBNRIND ne '' in the data step because I need the entire panel of Urinalysis tests and not just that particular test result. What would be the best approach here? I think transposing the data would be too messy but maybe putting the variables in an array/macro and utilising a do loop for those panel of tests?.
Update:I've tried this code but it doesn't keep the corresponding tests for where lb_nrind >0. If I apply the sum(lb_nrind > '' ) the same when applying lb_nrind > '' to the having clause
*proc sql;
*create table want as
select * from labUA
group by ptno and day and lb_cat
having sum(lb_nrind > '') > 0 ;
data want2;
do _n_ = 1 by 1 until (last.ptno);
set labUA;
by ptno period day hour ;
if not flag_group then flag_group = (lb_nrind > '');
end;
do _n_ = 1 to _n_;
set want;
if flag_group then output;
end;
drop flag_group; run;*
You can use a SQL HAVING clause to retain rows of a group meeting some aggregate condition. In your case that group might be a patientid, panelid and condition at least one LBNRIND not NULL
Example:
Consider this example where a group of rows is to be kept only if at least one of the rows in the group meets the criteria result7=77
Both code blocks use the SAS feature that a logical evaluation is 1 for true and 0 for false.
SQL
data have;
infile datalines missover;
input id test $ parm $ result1-result10;
datalines;
1 A P 1 2 . 9 8 7 . . . .
1 B Q 1 2 3
1 C R 4 5 6
1 D S 8 9 . . . 6 77
1 E T 1 1 1
1 F U 1 1 1
1 G V 2
2 A Z 3
2 B K 1 2 3 4 5 6 78
2 C L 4
2 D M 9
3 G N 8
4 B Q 7
4 D S 6
4 C 1 1 1 . . 5 0 77
;
proc sql;
create table want as
select * from have
group by id
having sum(result7=77) > 0
;
DOW Loop
data want;
do _n_ = 1 by 1 until (last.id);
set have;
by id;
if not flag_group then flag_group = (result7=77);
end;
do _n_ = 1 to _n_;
set have;
if flag_group then output;
end;
drop flag_group;
run;
I have a sample that include two variables: ID and ym. ID id refer to the specific ID for each trader and ym refer to the year-month variable. And I want to create a variable that show the number of years over the 10 years period prior month t as shown in the following figure.
ID ym Want
1 200101 0
1 200301 1
1 200401 2
1 200501 3
1 200601 4
1 200801 5
1 201201 5
1 201501 4
2 200001 0
2 200203 1
2 200401 2
2 200506 3
I attempt to use by function and fisrt.id to count the number.
data want;
set have;
want+1;
by id;
if first.id then want=1;
run;
However, the year in ym is not continuous. When the time gap is higher than 10 years, this method is not working. Although I assume I need to count the number of year in a rolling window (10 years), I am not sure how to achieve it. Please give me some suggestions. Thanks.
Just do a self join in SQL. With your coding of YM it is easy to do interval that is a multiple of a year, but harder to do other intervals.
proc sql;
create table want as
select a.id,a.ym,count(b.ym) as want
from have a
left join have b
on a.id = b.id
and (a.ym - 1000) <= b.ym < a.ym
group by a.id,a.ym
order by a.id,a.ym
;
quit;
This method retains the previous values for each ID and directly checks to see how many are within 120 months of the current value. It is not optimized but it works. You can set the array m() to the maximum number of values you have per ID if you care about efficiency.
The variable d is a quick shorthand I often use which converts years/months into an integer value - so
200012 -> (2000*12) + 12 = 24012
200101 -> (2001*12) + 1 = 24013
time from 200012 to 200101 = 24013 - 24012 = 1 month
data have;
input id ym;
datalines;
1 200101
1 200301
1 200401
1 200501
1 200601
1 200801
1 201201
1 201501
2 200001
2 200203
2 200401
2 200506
;
proc sort data=have;
by id ym;
data want (keep=id ym want);
set have;
by id;
retain seq m1-m100;
array m(100) m1-m100;
** Convert date to comparable value **;
d = 12 * floor(ym/100) + mod(ym,10);
** Initialize number of previous records **;
want = 0;
** If first record, set retained values to missing and leave want=0 **;
if first.id then call missing(seq,of m1-m100);
** Otherwise loop through previous months and count how many were within 120 months **;
else do;
do i = 1 to seq;
if d <= (m(i) + 120) then want = want + 1;
end;
end;
** Increment variables for next iteration **;
seq + 1;
m(seq) = d;
run;
proc print data=want noobs;
I don't know how to describe this question but here is an example. I have an initial dataset looks like this:
input first second $3.;
cards;
1 A
1 B
1 C
1 D
2 E
2 F
3 S
3 A
4 C
5 Y
6 II
6 UU
6 OO
6 N
7 G
7 H
...
;
I want an output dataset like this:
input first second $;
cards;
1 "A,B,C,D"
2 "E,F"
3 "S,A"
4 "C"
5 "Y"
6 "II,UU,OO,N"
7 "G,H"
...
;
Both tables will have two columns. Unique value of range of the column "first" could be 1 to any number.
Can someone help me ?
something like below
proc sort data=have;
by first second;
run;
data want(rename=(b=second));
length new_second $50.;
do until(last.first);
set have;
by first second ;
new_second =catx(',', new_second, second);
b=quote(strip(new_second));
end;
drop second new_second;
run;
output is
first second
1 "A,B,C,D"
2 "E,F"
3 "A,S"
4 "C"
5 "Y"
6 "II,N,OO,UU"
7 "G,H"
You can use by-group processing and the retain function to achieve this.
Create a sample dataset:
data have;
input id value $3.;
cards;
1 A
1 B
1 C
1 D
2 E
2 F
3 S
3 A
4 C
5 Y
6 II
6 UU
6 OO
6 N
7 G
7 H
;
run;
First ensure that your dataset is sorted by your id variable:
proc sort data=have;
by id;
run;
Then use the first. and last. notation to identify when the id variable is changing or about to change. The retain statement tells the datastep to keep the value within concatenated_value over observations rather than resetting it to a blank value. Use the quote() function to apply the " chars around the result before outputting the record. Use the cats() function to perform the actual concatenation and separate the records with a ,.
data want;
length contatenated_value $500.;
set have;
by id;
retain contatenated_value ;
if first.id then do;
contatenated_value = '';
end;
contatenated_value = catx(',', contatenated_value, value);
if last.id then do;
contatenated_value = quote(cats(contatenated_value));
output;
end;
drop value;
run;
Output:
contatenated_
value id
"A,B,C,D" 1
"E,F" 2
"S,A" 3
"C" 4
"Y" 5
"II,UU,OO,N" 6
"G,H" 7
I want to output the last value of a variable pr. sub-group to a SAS dataset, preferably in just a few steps. The code below do it, but I was hoping to do it in one step a la by variable; if last.variable then output; as for the case with just 1 by-variable.
data two;
input year firm price;
cards;
1 1 48
1 1 45
2 2 50
1 2 42
2 1 41
2 2 51
2 1 52
1 1 43
1 2 52;
run;
proc sort data = two;by year firm;run;
/* a) Create id across both sub-groups */
data two1;
set two;
by year firm;
retain case_id;
if FIRST.year OR first.firm then case_id + 1;
run;
/* b) Use id to output last values across both by-groups */
data two2;
set two1;
by case_id;
if last.case_id then output;
run;
proc print data = two1;run;
proc print data = two2;run;
With just 1 by-variable the two steps marked a) and b) can be combined. Is it possible with more than one by-group?
In data step a) add condition if lst.firm then output two2.
The final code should looks like:
data two1 two2;
set two;
by year firm;
retain case_id;
if FIRST.year OR first.firm then case_id + 1;
if last.firm then output two2;
output two1;
run;
Say you have three separate data sets consisting of the same number of observations. Each observation has an ID letter, A-Z, followed by some numerical observation. For example:
Data set 1:
B 3 8 1 9 4
C 4 1 9 3 1
A 4 4 5 4 9
Data set 2:
C 3 1 9 4 0
A 4 1 2 0 0
B 0 3 3 1 8
I want to merge the data sets BY that first variable. The problem is, the first variable is NOT already sorted in alphabetical form, and I do not want to sort it in alphabetical form. I want to merge the data but keep the original order. For example, I would get:
Merged data:
B 3 8 1 9 4
B 0 3 3 1 8
C 4 1 9 3 1
C 3 1 9 4 0
A 4 4 5 4 9
A 4 1 2 0 0
Is there any way to do this?
You can create a variable that holds the order and then apply that the new dataset after its "merged". I believe this is an append rather than merge though. I've used a format, though you could use a sql or data set merge as well.
data have1;
input id $ var1-var5;
cards;
B 3 8 1 9 4
C 4 1 9 3 1
A 4 4 5 4 9
;
run;
data have2;
input id $ var1-var5;
cards;
C 3 1 9 4 0
A 4 1 2 0 0
B 0 3 3 1 8
;
run;
data order;
set have1;
fmtname='sort_order';
type='J';
label=_n_;
start=id;
keep id fmtname type label start;
run;
proc format cntlin=order;
run;
data want;
set have1 have2;
order_var=input(id, $sort_order.);
run;
proc sort data=want;
by order_var;
run;
This is just one SQL version which follows along a similar path to Joe's answer. Row order is input via a sub-query rather than a format. However the initial order of the two input tables is lost in the join to the row order sub-query. The original order (have2 follows have1) is re-instated by using the table names as a secondary order variable.
proc sql;
create table want1 as
select want.id
,want.var1
,want.var2
,want.var3
,want.var4
,want.var5
from (
select *
, 'have1' as source
from have1
union all
select *
, 'have2' as source
from have2
) as want
left join
(
select id
, monotonic() as row_no
from have1
) as order
on want.id eq order.id
order by order.row_no
,want.source
;
quit;
proc compare
base=want1
compare=want
;
run;
And this is a data step version without a format. Here the have1 table with row order is re-merged with the concatenated data (have1 and have2) and then re-sorted by row order.
data want2;
set have1 have2;
run;
data have1;
set have1;
order_var = _n_;
run;
proc sort data=want2;
by id;
run;
proc sort data=have1;
by id;
run;
data want2;
merge want2 have1;
by id;
run;
proc sort data=want2;
by order_var;
run;
proc compare
base=want2
compare=want
;
run;