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This is a vectorised version of switch(): you can replace numeric values based on their position or their name,
and character or factor values only by their name. This is an S3 generic: {poorman} provides methods for
numeric, character, and factors. For logical vectors, use if_else(). For more complicated criteria, use
case_when().
You can use recode() directly with factors; it will preserve the existing order of levels while changing the
values. Alternatively, you can use recode_factor(), which will change the order of levels to match the order of
replacements.
This is a direct port of the dplyr::recode() function.
recode(.x, ..., .default = NULL, .missing = NULL)recode_factor(.x, ..., .default = NULL, .missing = NULL, .ordered = FALSE)
A vector to modify
Replacements. For character and factor .x, these should be named and replacement is based only on
their name. For numeric .x, these can be named or not. If not named, the replacement is done based on position
i.e. .x represents positions to look for in replacements. See examples.
When named, the argument names should be the current values to be replaced, and the argument values should be the new (replacement) values.
All replacements must be the same type, and must have either length one or the same length as .x.
If supplied, all values not otherwise matched will be given this value. If not supplied and if the
replacements are the same type as the original values in .x, unmatched values are not changed. If not supplied and
if the replacements are not compatible, unmatched values are replaced with NA.
.default must be either length 1 or the same length as .x.
If supplied, any missing values in .x will be replaced by this value. Must be either length 1 or
the same length as .x.
logical(1). If TRUE, recode_factor() creates an ordered factor.
A vector the same length as .x, and the same type as
the first of ..., .default, or .missing.
recode_factor() returns a factor whose levels are in the same order as
in .... The levels in .default and .missing come last.
na_if() to replace specified values with a NA.
coalesce() to replace missing values with a specified value.
replace_na() to replace NA with a value.
# NOT RUN {
# For character values, recode values with named arguments only. Unmatched
# values are unchanged.
char_vec <- sample(c("a", "b", "c"), 10, replace = TRUE)
recode(char_vec, a = "Apple")
recode(char_vec, a = "Apple", b = "Banana")
# Use .default as replacement for unmatched values. Note that NA and
# replacement values need to be of the same type.
recode(char_vec, a = "Apple", b = "Banana", .default = NA_character_)
# Throws an error as NA is logical, not character.
# }
# NOT RUN {
recode(char_vec, a = "Apple", b = "Banana", .default = NA)
# }
# NOT RUN {
# For numeric values, named arguments can also be used
num_vec <- c(1:4, NA)
recode(num_vec, `2` = 20L, `4` = 40L)
# Or if you don't name the arguments, recode() matches by position.
# (Only works for numeric vector)
recode(num_vec, "a", "b", "c", "d")
# .x (position given) looks in (...), then grabs (... value at position)
# so if nothing at position (here 5), it uses .default or NA.
recode(c(1, 5, 3), "a", "b", "c", "d", .default = "nothing")
# Note that if the replacements are not compatible with .x,
# unmatched values are replaced by NA and a warning is issued.
recode(num_vec, `2` = "b", `4` = "d")
# use .default to change the replacement value
recode(num_vec, "a", "b", "c", .default = "other")
# use .missing to replace missing values in .x
recode(num_vec, "a", "b", "c", .default = "other", .missing = "missing")
# For factor values, use only named replacements
# and supply default with levels()
factor_vec <- factor(c("a", "b", "c"))
recode(factor_vec, a = "Apple", .default = levels(factor_vec))
# Use recode_factor() to create factors with levels ordered as they
# appear in the recode call. The levels in .default and .missing
# come last.
recode_factor(num_vec, `1` = "z", `2` = "y", `3` = "x")
recode_factor(num_vec, `1` = "z", `2` = "y", `3` = "x", .default = "D")
recode_factor(num_vec, `1` = "z", `2` = "y", `3` = "x", .default = "D", .missing = "M")
# When the input vector is a compatible vector (character vector or
# factor), it is reused as default.
recode_factor(letters[1:3], b = "z", c = "y")
recode_factor(factor(letters[1:3]), b = "z", c = "y")
# }
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