Its purpose is to start the data step and assign a name to the SAS data set. This statement is only necessary when data is read from an external file. This statement defines the name, location and type of each variable to be read into the data set. Column input is the most basic type of input statement. With column input, the variable name is followed by the column numbers indicating where the data are located.
Variables are numeric by default.
The first variable, name , is a character variable located in columns 1 through 8. The second variable, age , is numeric and located in columns 11 and 12. List input is similar to column input, except that column numbers are omitted. Formatted input specifies a data format after each variable name. The data format indicates the data type and field width.