R: Select several rows and columns from a data object
sel
R Documentation
Select several rows and columns from a data object
Description
This function acts similarly as the [] operator, i.e. selects rows and columns of a data
object.
Usage
sel(x, ...)
## S3 method for class 'farules'
sel(x,
i=rep(TRUE,
nrow(x)),
...)
## S3 method for class 'fsets'
sel(x,
i=rep(TRUE, nrow(x)),
j=rep(TRUE, ncol(x)),
...)
Arguments
x
Original data: originally an instance of class fsets or farules.
i
The specification of rows to be selected. It can be a vector of integer indices which have
to be selected, or vector of negative integers specifying which rows to discard, or
vector of logical values etc. See [ for details.
j
The specification of columns to be selected (only applicable for instances of
fsets). It can be a vector of integer indices which have
to be selected, or vector of negative integers specifying which columns to discard, or
vector of logical values etc. See [ for details.
...
Other parameters to some methods.
Details
Originally, it is an S3 method defined for fsets and farules
classes.
For instances of the fsets class, sel behaves similarly as the []
operator except that it also takes care of the vars and specs
attributes. Therefore, if you want to select some rows or columns from the fsets
object and obtain again a valid fsets object, use sel. If you want only
a matrix or vector of membership degrees in the fsets object without any other
attributes, use the [] operator.
For instances of the farules class, sel returns a valid
farules object with a subset of rules specified with the i argument. Also
the matrix of statistics is handled appropriately.
Value
A subset of data (originally fsets or farules) of the same type as
original data, with attributes and additional meta data handled correctly.
x <- 0:100
d <- fcut(x,
breaks=c(0, 25, 50, 75, 100),
type='triangle')
# select only first two columns
res <- sel(d, , 1:2)
print(res)
# select only the 3rd row
res <- sel(d, 3)
print(res)
providing 
.