datawizard (version 0.13.0)

recode_into: Recode values from one or more variables into a new variable

Description

This functions recodes values from one or more variables into a new variable. It is a convenient function to avoid nested ifelse() statements, which is similar to dplyr::case_when().

Usage

recode_into(
  ...,
  data = NULL,
  default = NA,
  overwrite = TRUE,
  preserve_na = FALSE,
  verbose = TRUE
)

Value

A vector with recoded values.

Arguments

...

A sequence of two-sided formulas, where the left hand side (LHS) is a logical matching condition that determines which values match this case. The LHS of this formula is also called "recode pattern" (e.g., in messages). The right hand side (RHS) indicates the replacement value.

data

Optional, name of a data frame. This can be used to avoid writing the data name multiple times in .... See 'Examples'.

default

Indicates the default value that is chosen when no match in the formulas in ... is found. If not provided, NA is used as default value.

overwrite

Logical, if TRUE (default) and more than one recode pattern apply to the same case, already recoded values will be overwritten by subsequent recode patterns. If FALSE, former recoded cases will not be altered by later recode patterns that would apply to those cases again. A warning message is printed to alert such situations and to avoid unintentional recodings.

preserve_na

Logical, if TRUE and default is not NA, missing values in the original variable will be set back to NA in the recoded variable (unless overwritten by other recode patterns). If FALSE, missing values in the original variable will be recoded to default. Setting preserve_na = TRUE prevents unintentional overwriting of missing values with default, which means that you won't find valid values where the original data only had missing values. See 'Examples'.

verbose

Toggle warnings.

Examples

x <- 1:30
recode_into(
  x > 15 ~ "a",
  x > 10 & x <= 15 ~ "b",
  default = "c"
)

x <- 1:10
# default behaviour: second recode pattern "x > 5" overwrites
# some of the formerly recoded cases from pattern "x >= 3 & x <= 7"
recode_into(
  x >= 3 & x <= 7 ~ 1,
  x > 5 ~ 2,
  default = 0,
  verbose = FALSE
)

# setting "overwrite = FALSE" will not alter formerly recoded cases
recode_into(
  x >= 3 & x <= 7 ~ 1,
  x > 5 ~ 2,
  default = 0,
  overwrite = FALSE,
  verbose = FALSE
)

set.seed(123)
d <- data.frame(
  x = sample(1:5, 30, TRUE),
  y = sample(letters[1:5], 30, TRUE),
  stringsAsFactors = FALSE
)

# from different variables into new vector
recode_into(
  d$x %in% 1:3 & d$y %in% c("a", "b") ~ 1,
  d$x > 3 ~ 2,
  default = 0
)

# no need to write name of data frame each time
recode_into(
  x %in% 1:3 & y %in% c("a", "b") ~ 1,
  x > 3 ~ 2,
  data = d,
  default = 0
)

# handling of missing values
d <- data.frame(
  x = c(1, NA, 2, NA, 3, 4),
  y = c(1, 11, 3, NA, 5, 6)
)
# first NA in x is overwritten by valid value from y
# we have no known value for second NA in x and y,
# thus we get one NA in the result
recode_into(
  x <= 3 ~ 1,
  y > 5 ~ 2,
  data = d,
  default = 0,
  preserve_na = TRUE
)
# first NA in x is overwritten by valid value from y
# default value is used for second NA
recode_into(
  x <= 3 ~ 1,
  y > 5 ~ 2,
  data = d,
  default = 0,
  preserve_na = FALSE
)