The values of string variables can contain numbers,
letters, and special characters and can be up to 32,767 bytes.
System-missing values cannot be generated for string
variables, since any character is a legal string value.
When a transformation command that creates or modifies
a string variable yields a missing or undefined result, a null string
is assigned. The variable displays as blanks and is not treated as
missing.
String formats are used to read and write string
variables. The input values can be alphanumeric characters (A format) or the hexadecimal representation
of alphanumeric characters (AHEX format).
For fixed-format raw data, the width can be explicitly
specified on commands such as DATA LIST and GET DATA or implied if column-style specifications are used. For
freefield data, the default width is 1; if the input string may be
longer, w must be explicitly
specified. Input strings shorter than the specified width are right-padded
with blanks.
The output format for a string variable is always A. The width is determined by the input format or the format assigned
on the STRING command. Once defined, the width of a string
variable can only be changed with the ALTER TYPE command.