misty (version 0.5.0)

rec: Recode Variable

Description

This function recodes numeric vectors, character vectors, or factors according to recode specifications.

Usage

rec(x, spec, as.factor = FALSE, levels = NULL, names = ".r", as.na = NULL,
    table = FALSE, check = TRUE)

Value

Returns a numeric vector or data frame with the same length or same number of rows as x containing the recoded coded variable(s).

Arguments

x

a numeric vector, character vector, factor, matrix or data frame.

spec

a character string of recode specifications (see 'Details').

as.factor

logical: if TRUE, character vector will be coerced to a factor.

levels

a character vector for specifying the levels in the returned factor.

as.na

a numeric vector indicating user-defined missing values, i.e. these values are converted to NA before conducting the analysis.

names

a character string or character vector indicating the names of the recoded variables when specifying more than one variable. By default, variables are named with the ending ".r" resulting in e.g. "x1.r" and "x2.r". Variable names can also be specified using a character vector matching the number of variables specified in x (e.g., names = c("recode.x1", "recode.x2")).

table

logical: if TRUE, a cross table variable x recoded variable is printed on the console if only one variable is specified in x.

check

logical: if TRUE, argument specification is checked.

Author

Takuya Yanagida

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 in 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 (lowest value) and hi (highest value) may appear in a range. For example, lo:10 = 1. Note that : is not the R sequence operator. In addition you may not use : with the collect operator, e.g., c(1, 3, 5:7) will cause an error.

- else For example, else = NA. Everything that does not fit a previous specification. Note that else matches all otherwise unspecified values on input, including NA.

References

Fox, J., & Weisberg S. (2019). An R Companion to Applied Regression (3rd ed.). Thousand Oaks CA: Sage. URL: https://socialsciences.mcmaster.ca/jfox/Books/Companion/

See Also

item.reverse

Examples

#--------------------------------------
# Numeric vector
x.num <- c(1, 2, 4, 5, 6, 8, 12, 15, 19, 20)

# Recode 5 = 50 and 19 = 190
rec(x.num, "5 = 50; 19 = 190")

# Recode 1, 2, and 5 = 100 and 4, 6, and 7 = 200 and else = 300
rec(x.num, "c(1, 2, 5) = 100; c(4, 6, 7) = 200; else = 300")

# Recode lowest value to 10 = 100 and 11 to highest value = 200
rec(x.num, "lo:10 = 100; 11:hi = 200")

# Recode 5 = 50 and 19 = 190 and check recoding
rec(x.num, "5 = 50; 19 = 190", table = TRUE)

#--------------------------------------
# Character vector
x.chr <- c("a", "c", "f", "j", "k")

# Recode a to x
rec(x.chr, "'a' = 'X'")

# Recode a and f to x, c and j to y, and else to z
rec(x.chr, "c('a', 'f') = 'x'; c('c', 'j') = 'y'; else = 'z'")

# Recode a to x and coerce to a factor
rec(x.chr, "'a' = 'X'", as.factor = TRUE)

#--------------------------------------
# Factor
x.fac <- factor(c("a", "b", "a", "c", "d", "d", "b", "b", "a"))

# Recode a to x, factor levels ordered alphabetically
rec(x.fac, "'a' = 'x'")

# Recode a to x, user-defined factor levels
rec(x.fac, "'a' = 'x'", levels = c("x", "b", "c", "d"))

#--------------------------------------
# Multiple variables
dat <- data.frame(x1.num = c(1, 2, 4, 5, 6),
                  x2.num = c(5, 19, 2, 6, 3),
                  x1.chr = c("a", "c", "f", "j", "k"),
                  x2.chr = c("b", "c", "a", "d", "k"),
                  x1.fac = factor(c("a", "b", "a", "c", "d")),
                  x2.fac = factor(c("b", "a", "d", "c", "e")))

# Recode numeric vector and attach to 'dat'
dat <- cbind(dat,
             rec(dat[, c("x1.num", "x2.num")], "5 = 50; 19 = 190"))

# Recode character vector and attach to 'dat'
dat <- cbind(dat,
             rec(dat[, c("x1.chr", "x2.chr")], "'a' = 'X'"))

# Recode factor vector and attach to 'dat'
dat <- cbind(dat,
             rec(dat[, c("x1.fac", "x2.fac")], "'a' = 'X'"))