R: Merge Levels of a Factor

mergeLevels {spatstat} | R Documentation

## Merge Levels of a Factor

### Description

Specified levels of the factor will be merged into a single level.

### Usage

    mergeLevels(.f, ...)

### Arguments

`.f` | A factor (or a factor-valued pixel image or a point pattern with factor-valued marks).
`...` | List of `name=value` pairs, where `name` is the new merged level, and `value` is the vector of old levels that will be merged.

### Details

This utility function takes a factor `.f` and merges specified levels of the factor.

The grouping is specified by the arguments `...` which must each be given in the form `new=old`, where `new` is the name for the new merged level, and `old` is a character vector containing the old levels that are to be merged.

The result is a new factor (or factor-valued object), in which the levels listed in `old` have been replaced by a single level `new`.

An argument of the form `name=character(0)` or `name=NULL` is interpreted to mean that all other levels of the old factor should be mapped to `name`.

### Value

Another factor of the same length as `.f` (or object of the same kind as `.f`).

### Tips for manipulating factor levels

To remove unused levels from a factor `f`, just type `f <- factor(f)`.

To change the ordering of levels in a factor, use `factor(f, levels=l)` or `relevel(f, ref)`.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

Rolf Turner r.turner@auckland.ac.nz

and Ege Rubak rubak@math.aau.dk

### See Also

`factor`, `relevel`

### Examples

       likert <- c("Strongly Agree", "Agree", "Neutral",
                   "Disagree", "Strongly Disagree")
       answers <- factor(sample(likert, 15, replace=TRUE), levels=likert)
       answers
       mergeLevels(answers, Positive=c("Strongly Agree", "Agree"),
                            Negative=c("Strongly Disagree", "Disagree"))

[Package spatstat version 1.54-0 Index]