10.3 FILTERING ALGORITHMS 395
and look at its associated object editor, which defines what the filter does and
the parameters it takes.
Unsupervised attribute filters
Table 10.1 lists Weka’s unsupervised attribute filters. Many of the operations
were introduced in Section 7.3.
Adding and removing attributes
Addinserts an attribute at a given position, whose value is declared to be missing
for all instances. Use the generic object editor to specify the attribute’s name,
where it will appear in the list of attributes, and its possible values (for nominal
attributes).Copycopies existing attributes so that you can preserve them when
experimenting with filters that overwrite attribute values. Several attributes can
be copied together using an expression such as 1–3for the first three attributes,
(b)
Figure 10.16(continued)