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Create a Key-Value Mapping for Format Creation

Source: R/utilities.R
fmap.Rd

Convenience helper for building data-driven formats with fnew. Returns a named vector (or list) with class "ks_fmap" that signals fnew() to use the natural direction: names are input keys, values are output labels/objects — regardless of the format type.

Usage

fmap(keys, values)

Arguments

keys

Character vector of input keys (lookup values).

values

Vector of output labels or objects (character, numeric, Date, POSIXct, logical, etc.).

Value

A named vector (or list, for non-atomic values) with class c("ks_fmap", <original class>). Names are keys, values are values.

Details

Without fmap(), fnew() reverses named vectors for character and numeric types (the factor() convention c(Label = "Code")). Wrapping your data in fmap() suppresses this reversal, so fmap(keys, values) works identically for character, numeric, Date, POSIXct, and logical formats.

See also

fnew for format creation.

Examples

# Character lookup: keys -> labels
fmap(c("M", "F"), c("Male", "Female")) |> fnew(name = "sex")
fput(c("M", "F"), "sex")
#> [1] "Male"   "Female"
fclear()
#> All formats cleared from library.

# Date lookup from a data frame
ids   <- c("SUBJ-001", "SUBJ-002")
dates <- as.Date(c("2023-03-09", "2024-08-13"))
fmap(ids, dates) |> fnew(type = "Date", name = "icdtn")
fput("SUBJ-001", "icdtn")
#> [1] "2023-03-09"
fclear()
#> All formats cleared from library.