An input format describes how to interpret the contents of an
input field as a number or a string. It might specify that the field
contains an ordinary decimal number, a time or date, a number in binary
or hexadecimal notation, or one of several other notations. Input
formats are used by commands such as DATA LIST that read data or
syntax files into the PSPP active dataset.
Every input format corresponds to a default output format that specifies the formatting used when the value is output later. It is always possible to explicitly specify an output format that resembles the input format. Usually, this is the default, but in cases where the input format is unfriendly to human readability, such as binary or hexadecimal formats, the default output format is an easier-to-read decimal format.
Every variable has two output formats, called its print format and
write format. Print formats are used in most output contexts;
write formats are used only by WRITE (see WRITE). Newly
created variables have identical print and write formats, and
FORMATS, the most commonly used command for changing formats
(see FORMATS), sets both of them to the same value as well. Thus,
most of the time, the distinction between print and write formats is
unimportant.
Input and output formats are specified to PSPP with
a format specification of the
form TYPEw or TYPEw.d, where
TYPE is one of the format types described later, w is a
field width measured in columns, and d is an optional number of
decimal places. If d is omitted, a value of 0 is assumed. Some
formats do not allow a nonzero d to be specified.
The following sections describe the input and output formats supported by PSPP.