I have 36 columns and 3600 rows and some columns contains all missing values. After I posted the response to your answer, I realize that was not the best way to express my question. The question really was that I'd love to select some rows from those columns and then combine them into one column. And I know exactly which ones I need from each column. In the example, I want to select the first 2 observations from column x1, the 2-4th from column x2, the 5th-7th in column x3, and 8th in column x4 and combine those values into one column x. I can use multiple (if _n_>a and _n_<b, then x=xi)statements to do this, but I'm wondering if there is a more elegant way to do this?
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