如何对一列数据进行每2个数据求和

shiyiming

请问，如何对一列数据进行每2个数据求和，如左结果为3， 7 ，11。谢谢
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shiyiming

DATA SUM;
  INPUT NUMBER;
  RETAIN PREVIOUSNUM ;
  IF MOD(_N_,2)= 0 THEN DO;
          SUM=PREVIOUSNUM+NUMBER;
        OUTPUT;
  END;
  PREVIOUSNUM=NUMBER;
  KEEP SUM;
DATALINES;
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;
RUN;

shiyiming

DATA SUM;
set d;
RETAIN PREVIOUSNUM ;
IF MOD(_N_,6)= 0 THEN DO;
SUM=PREVIOUSNUM+market_return;
OUTPUT;
END;
PREVIOUSNUM=market_return;
KEEP SUM;
RUN;


thank you very much!!

shiyiming

上面程序是对两个数求和，如果是3个或者4个数呢？弱弱的问一句，MOD(_N_,6)函数是什么意思，怎么用呢？

Qiong

[code:128gdxp7]data temp;
do i=1 to 20;
output;
end;
run;

%let interval=3;
%let var=i;

data new;
set temp;
flag=ceilz(_n_/%eval(&interval));
run;

proc sql noprint;
create table new as select distinct   flag, sum(&var) as sum
from new
group by flag
order by flag;
quit;[/code:128gdxp7]

shiyiming

data b;
  set a end = endobs;
   sum + i;
   IF MOD(_N_,2)= 0 THEN OUTPUT;
   sum = i;
   keep sum;
run;

shiyiming

data a;
input x;
input y;
z=x+y;

datalines;
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;