R: Recode a Variable

recode {car}

R Documentation

Recode a Variable

Description

Recodes a numeric vector, character vector, or factor according to simple recode specifications.

Usage

recode(var, recodes, as.factor.result, as.numeric.result=TRUE, levels)

Arguments

`var`	numeric vector, character vector, or factor.
`recodes`	character string of recode specifications: see below.
`as.factor.result`	return a factor; default is `TRUE` if `var` is a factor, `FALSE` otherwise.
`as.numeric.result`	if `TRUE` (the default), and `as.factor.result` is `FALSE`, then the result will be coerced to numeric if all values in the result are numerals—i.e., represent numbers.
`levels`	an optional argument specifying the order of the levels in the returned factor; the default is to use the sort order of the level names.

Details

Recode specifications appear in a character string, separated by semicolons (see the examples below), of the form input=output. If an input value satisfies more than one specification, then the first (from left to right) applies. If no specification is satisfied, then the input value is carried over to the result. NA is allowed on input and output. Several recode specifications are supported:

single value: For example, 0=NA.
vector of values: For example, c(7,8,9)='high'.
range of values: For example, 7:9='C'. The special values lo and hi may appear in a range. For example, lo:10=1. Note: : is not the R sequence operator.
else: everything that does not fit a previous specification. For example, else=NA. Note that else matches all otherwise unspecified values on input, including NA.

If all of the output values are numeric, and if as.factor.result is FALSE, then a numeric result is returned; if var is a factor, then by default so is the result.

Value

a recoded vector of the same length as var.

Author(s)

John Fox jfox@mcmaster.ca

References

Fox, J. and Weisberg, S. (2011) An R Companion to Applied Regression, Second Edition, Sage.

Examples

x<-rep(1:3,3)
x
## [1] 1 2 3 1 2 3 1 2 3
recode(x, "c(1,2)='A'; 
	else='B'")
## [1] "A" "A" "B" "A" "A" "B" "A" "A" "B"
recode(x, "1:2='A'; 3='B'")
## [1] "A" "A" "B" "A" "A" "B" "A" "A" "B"

[Package car version 2.0-12 Index]