R: Combine factor levels

combine_factor {reshape} | R Documentation

## Combine factor levels

### Description

Convenience function to make it easy to combine multiple levels

### Usage

    combine_factor(fac, variable=levels(fac), other.label="Other")

### Arguments

`fac` | factor variable
`variable` | either a vector of . See examples for more details.
`other.label` | label for other level

### Author(s)

Hadley Wickham <h.wickham@gmail.com>

### Examples

    df <- data.frame(a = LETTERS[sample(5, 15, replace=TRUE)], y = rnorm(15))
    combine_factor(df$a, c(1,2,2,1,2))
    combine_factor(df$a, c(1:4, 1))
    (f <- reorder(df$a, df$y))
    percent <- tapply(abs(df$y), df$a, sum)
    combine_factor(f, c(order(percent)[1:3]))

[Package reshape version 0.8.8 Index]