Ordinal Categorical Arrays
In this section...
“Order of Categories” on page 8-46
“How to Create Ordinal Categorical Arrays” on page 8-46
“Working with Ordinal Categorical Arrays” on page 8-48Order of Categories
categorical is a data type to store data with values from a finite set of discrete
categories, which can have a natural order. You can specify and rearrange the order of
categories in all categorical arrays. However, you only can treat ordinal categorical arrays
as having a mathematical ordering to their categories. Use an ordinal categorical array if
you want to use the functions min, max, or relational operations, such as greater than and
less than.The discrete set of pet categories {'dog' 'cat' 'bird'} has no meaningful
mathematical ordering. You are free to use any category order and the meaning of the
associated data does not change. For example, pets =
categorical({'bird','cat','dog','dog','cat'}) creates a categorical array
and the categories are listed in alphabetical order, {'bird' 'cat' 'dog'}. You can
choose to specify or change the order of the categories to {'dog' 'cat' 'bird'} and
the meaning of the data does not change.ordinal categorical arrays contain categories that have a meaningful mathematical
ordering. For example, the discrete set of size categories {'small', 'medium',
'large'} has the mathematical ordering small < medium < large. The first
category listed is the smallest and the last category is the largest. The order of the
categories in an ordinal categorical array affects the result from relational comparisons of
ordinal categorical arrays.How to Create Ordinal Categorical Arrays
This example shows how to create an ordinal categorical array using the categorical
function with the 'Ordinal',true name-value pair argument.8 Categorical Arrays