droplevels

(Not Recommended) Drop levels from a nominal or ordinal array

The nominal and ordinal array data types are not recommended. To represent ordered and unordered discrete, nonnumeric data, use the Categorical Arrays data type instead.

Syntax

B = droplevels(A)

B = droplevels(A,oldlevels)

Description

B = droplevels(A) drops unused levels from the nominal or ordinal array A. The array B has the same size, type, and values as A, but has a list of potential levels that includes only those present in some element of A.

B = droplevels(A,oldlevels) removes the specified levels oldlevels from A.

droplevels removes levels, but does not remove elements. Elements of B that correspond to elements of A having levels in oldlevels all have an undefined level.

Examples

Drop Levels From an Ordinal Array

Bin patient ages into ordinal levels corresponding to 10-year intervals.

load hospital
edges = 0:10:100;
labels = strcat(num2str((0:10:90)','%d'),{'s'});
A = ordinal(hospital.Age,labels,[],edges);
getlabels(A)

ans = 1x10 cell
  Columns 1 through 7

    {'0s'}    {'10s'}    {'20s'}    {'30s'}    {'40s'}    {'50s'}    {'60s'}

  Columns 8 through 10

    {'70s'}    {'80s'}    {'90s'}

Drop any levels that have no patients in them.

A = droplevels(A);
getlabels(A)

ans = 1x4 cell
    {'20s'}    {'30s'}    {'40s'}    {'50s'}

Input Arguments

A — Nominal or ordinal array

nominal array | ordinal array

Nominal or ordinal array, specified as a nominal or ordinal array object created with nominal or ordinal.

oldlevels — Levels to remove

string array | cell array of character vectors | 2-D character matrix

Levels to remove from the nominal or ordinal array, specified as a string array, a cell array of character vectors, or a 2-D character matrix.

Data Types: char | string | cell

Output Arguments

B — Nominal or ordinal array

nominal array | ordinal array

Nominal or ordinal array, returned as a nominal or ordinal array object.