Just a couple of shortcuts. The rename statement changes the name of variable y, when the file is set, so that it will be seen to be variable _y; I did it that way so that the later missing values of y wouldn't override the desired value from the first record. The drop statement, then, just uses the semicolon as a wild card. It says, in essence, to drop any variable that starts with an underscore (i.e., variable _y). The semi colon has lots of under used useage in SAS as stated, nicely, in: http://www2.sas.com/ proceedings/sugi29/054-29.pdf
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