# Extract.fv

##### Extract or Replace Subset of Function Values

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

.

##### Usage

```
## S3 method for class 'fv':
[(x, i, j, \dots, drop=FALSE)
``` ## S3 method for class 'fv':
[(x, i, j) <- value

## S3 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"`

.

##### See Also

##### 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
```

*Documentation reproduced from package spatstat, version 1.41-1, License: GPL (>= 2)*