Extract or Replace Parts of a Factor (original) (raw)
| Extract.factor {base} | R Documentation |
|---|
Description
Extract or replace subsets of factors.
Usage
## S3 method for class 'factor'
x[..., drop = FALSE]
## S3 method for class 'factor'
x[[...]]
## S3 replacement method for class 'factor'
x[...] <- value
## S3 replacement method for class '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](../../stats/html/contrasts.html) 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
[factor](../../base/help/factor.html), [Extract](../../base/help/Extract.html).
Examples
## following example(factor)
(ff <- factor(substring("statistics", 1:10, 1:10), levels = letters))
ff[, drop = TRUE]
factor(letters[7:10])[2:3, drop = TRUE]
[Package _base_ version 4.6.0 Index]