The raw data file contains data that is free-format, meaning that the data is not arranged in columns or fixed fields.

List input should be used to read data that is free-format because you do not need to specify the column locations of the data.

You can use the DSD option in the FILE statement to specify that data values containing commas should be enclosed in quotation marks. The DSD option uses a comma as the delimiter by default.

Because the data is free-format, list input is used to read the values. With list input, you simply name each variable and identify its type.

The INFILE statement identifies the location of the external data file. The DLM= option specifies the colon (:) as the delimiter that separates each field.

You can use the MISSOVER option in the INFILE statement to read the missing values at the end of a record. The MISSOVER option prevents SAS from moving to the next record if values are missing in the current record.

The LENGTH statement extends the length of the character variable LastName so that it is large enough to accommodate the data. Variable attributes such as length are defined the first time a variable is named in a DATA step. The LENGTH statement should precede the INPUT statement so that the correct length is defined.

Notice that the values for School contain embedded blanks, and the values for Enrolled are nonstandard numeric values. Modified list input can be used to read the values that contain embedded blanks and nonstandard values.

The INPUT statement uses list input with format modifiers and informats to read the values for each variable. The ampersand (&) modifier enables you to read character values that contain single embedded blanks. The colon (:) modifier enables you to read nonstandard data values and character values that are longer than eight characters, but which contain no embedded blanks.

The values for Year can be read with column, formatted, or list input. However, the values for School and Enrolled are free-format data that contain embedded blanks or nonstandard values. Therefore, these last two variables must be read with modified list input.