R: Extract or Replace Subset of Function Values

Extract.fv {spatstat.core} | R Documentation

## Extract or Replace Subset of Function Values

### Description

Extract or replace a subset of an object of class `"fv"`.

### Usage

      ## S3 method for class 'fv'
    x[i, j, ..., drop=FALSE]

      ## S3 replacement method for class 'fv'
    x[i, j] <- value

      ## S3 replacement method for class 'fv'
    x$name <- value

### Arguments

`x` | a function value object, of class `"fv"` (see `fv.object`). Essentially a data frame.
`i` | any appropriate subset index. Selects a subset of the rows of the data frame, i.e. a subset of the domain of the function(s) represented by `x`.
`j` | any appropriate subset index for the columns of the data frame. Selects some of the functions present in `x`.
`name` | the name of a column of the data frame.
`...` | Ignored.
`drop` | Logical. If `TRUE`, the result is a data frame or vector containing the selected rows and columns of data. If `FALSE` (the default), the result is another object of class `"fv"`.
`value` | Replacement value for the column or columns selected by `name` or `j`.

### Details

These functions extract a designated subset of an object of class `"fv"`, or replace the designated subset with other data, or delete the designated subset.

The subset is specified by the row index `i` and column index `j`, or by the column name `name`. Either `i` or `j` may be missing, or both may be missing.

The function `[.fv` is a method for the generic operator `[` for the class `"fv"`. It extracts the designated subset of `x`, and returns it as another object of class `"fv"` (if `drop=FALSE`) or as a data frame or vector (if `drop=TRUE`).

The function `[<-.fv` is a method for the generic operator `[<-` for the class `"fv"`. If `value` is `NULL`, the designated subset of `x` will be deleted from `x`. Otherwise, the designated subset of `x` will be replaced by the data contained in `value`. The return value is the modified object `x`.

The function `$<-.fv` is a method for the generic operator `$<-` for the class `"fv"`. If `value` is `NULL`, the designated column of `x` will be deleted from `x`. Otherwise, the designated column of `x` will be replaced by the data contained in `value`. The return value is the modified object `x`.

### Value

The result of `[.fv` with `drop=TRUE` is a data frame or vector.

Otherwise, the result is another object of class `"fv"`.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner r.turner@auckland.ac.nz

### See Also

`fv.object`

### Examples

     K <- Kest(cells)

     # discard the estimates of K(r) for r  > 0.1
     Ksub <- K[K$r <= 0.1, ]

     # extract the border method estimates
     bor <- K[ , "border", drop=TRUE]
     # or equivalently
     bor <- K$border

     # remove the border-method estimates
     K$border <- NULL
     K

[Package spatstat.core version 2.3-0 Index]