fct | R Documentation |
fct()
is a stricter version of factor()
that errors if your
specification of levels
is inconsistent with the values in x
.
fct(x = character(), levels = NULL, na = character())
x |
A character vector. Values must occur in either |
levels |
A character vector of known levels. If not supplied, will
be computed from the unique values of |
na |
A character vector of values that should become missing values. |
A factor.
# Use factors when you know the set of possible values a variable might take x <- c("A", "O", "O", "AB", "A") fct(x, levels = c("O", "A", "B", "AB")) # If you don't specify the levels, fct will create from the data # in the order that they're seen fct(x) # Differences with base R ----------------------------------------------- # factor() silently generates NAs x <- c("a", "b", "c") factor(x, levels = c("a", "b")) # fct() errors try(fct(x, levels = c("a", "b"))) # Unless you explicitly supply NA: fct(x, levels = c("a", "b"), na = "c") # factor() sorts default levels: factor(c("y", "x")) # fct() uses in order of appearance: fct(c("y", "x"))
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