| subset {base} | R Documentation |
Subsetting Vectors and Data Frames
Description
Return subsets of vectors or data frames which meet conditions.
Usage
subset(x, ...)
subset.default(x, subset, ...)
subset.data.frame(x, subset, select, ...)
Arguments
x |
object to be subsetted |
... |
how to subset, depends on object |
subset |
logical expression |
select |
expression, indicating variables to select from a data frame |
Details
For ordinary vectors, the result is simply
x[subset & !is.na(subset)].
For data frames, the subset argument works similarly on the
rows. Note that subset will be evaluated in the data frame.
The select argument exists only for the method for data frames.
It works by
first replacing variable names in the selection expression with the
corresponding column numbers in the data frame and then using the
resulting integer vector to index the columns. This allows the use
of the standard indexing conventions so that for examples ranges of
variables can be specified easily.
Value
Selected rows and columns of the object x.
Author(s)
Peter Dalgaard
See Also
[,
transform
Examples
data(airquality)
subset(airquality, Temp > 80, select = c(Ozone, Temp))
subset(airquality, Day == 1, select = -Temp)
subset(airquality, select = Ozone:Wind)
attach(airquality)
subset(Ozone, Temp > 80)