Extract.factor
Extract or Replace Parts of a Factor
Extract or replace subsets of factors.
- Keywords
- category
Usage
# S3 method for factor
[(x, …, drop = FALSE)
# S3 method for factor
[[(x, …)
# S3 method for factor
[(x, …) <- value
# S3 method for factor
[[(x, …) <- value
Arguments
- x
a factor
- …
a specification of indices -- see
Extract
.- drop
logical. If true, unused levels are dropped.
- value
character: a set of levels. Factor values are coerced to character.
Details
When unused levels are dropped the ordering of the remaining levels is preserved.
If value
is not in levels(x)
, a missing value is
assigned with a warning.
Any contrasts
assigned to the factor are preserved
unless drop = TRUE
.
The [[
method supports argument exact
.
Value
A factor with the same set of levels as x
unless drop = TRUE
.
See Also
Examples
library(base)
# NOT RUN {
## following example(factor)
(ff <- factor(substring("statistics", 1:10, 1:10), levels = letters))
ff[, drop = TRUE]
factor(letters[7:10])[2:3, drop = TRUE]
# }
Community examples
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