【Length Statement】

To change the length of a char variable, the new length must be declared at first reference to the variable, thus before the variable is put into the PDV by INPUT or SET.

For numeric variables, the length statement can be anywhere in the DATA step, because has effect only when writing out to the data set.

This is a key difference between them, however, many data people don’t know it clearly though they use SAS for many years.

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