fct {forcats} | R Documentation |
Create a factor
Description
fct()
is a stricter version of factor()
that errors if your
specification of levels
is inconsistent with the values in x
.
Usage
fct(x = character(), levels = NULL, na = character())
Arguments
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. |
Value
A factor.
Examples
# 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"))
[Package forcats version 1.0.0 Index]