Transposing with DATA Steps
C.1 Transposing and Performance
We saw in Chapter 14 that the TRANSPOSE procedure can be used to transpose data in a very flexible way and with a clear syntax. PROC TRANSPOSE and the macros we presented in Chapter 14 are the first choice for data transpositions.
However, in situations where the number of subjects is in the hundreds of thousands, and the number of variables or repetitions is in the thousands, performance issues might arise. In these cases it is advisable to use a SAS DATA step instead of PROC TRANPOSE. ...