新手问个相当简单的问题

shiyiming

有变量x1-x99,
要定义新的变量y1=(x1+x2+x3)/3,y2=(x2+x3+x4)/3，以此类推，这个怎么实现？

shiyiming

y98,y99的公式是什么?

shiyiming

不好意思，忘说了，最后两个不计

shiyiming

[code:2qurng93]data raw(drop=i);
        array x{99};
        do i=1 to 99;
                x(i)=ceil(10*ranuni(1223456));
        end;
run;
data out(keep=y:);
        set raw;
        array x{*} x1-x99;
        array y{97};
        do i=1 to dim(y);
                y(i)=mean(x(i),x(i+1),x(i+2));
        end;
run;[/code:2qurng93]

shiyiming

3QU

shiyiming

to hopewell
小哥：他要除以3，你为什么给mean呢？

shiyiming

?????
[quote:2yjondhb]小哥：他要除以3，你为什么给mean呢？[/quote:2yjondhb]

shiyiming

when missing value exist, the mean will create  a no missing value if there are at least one no missing value present and logically the  denominator will not the 3.