# Extract.fasp

##### Extract Subset of Function Array

Extract a subset of a function array (an object of class
`"fasp"`

).

##### Usage

```
# S3 method for fasp
[(x, I, J, drop=TRUE,…)
```

##### Arguments

- x
A function array. An object of class

`"fasp"`

.- I
any valid expression for a subset of the row indices of the array.

- J
any valid expression for a subset of the column indices of the array.

- drop
Logical. When the selected subset consists of only one cell of the array, if

`drop=FALSE`

the result is still returned as a \(1 \times 1\) array of functions (class`"fasp"`

) while if`drop=TRUE`

it is returned as a function (class`"fv"`

).- …
Ignored.

##### Details

A function array can be regarded as a matrix whose entries
are functions. See `fasp.object`

for an explanation of
function arrays.

This routine extracts a sub-array according to the usual conventions for matrix indexing.

##### Value

A function array (of class `"fasp"`

).
Exceptionally, if the array has only one cell, and
if `drop=TRUE`

, then the result is a function value table
(class `"fv"`

).

##### See Also

##### Examples

```
# NOT RUN {
# Lansing woods data - multitype points with 6 types
woods <- lansing
# }
# NOT RUN {
# compute 6 x 6 array of all cross-type K functions
a <- alltypes(woods, "K")
# extract first three marks only
b <- a[1:3,1:3]
# }
# NOT RUN {
plot(b)
# }
# NOT RUN {
# subset of array pertaining to hickories
h <- a[levels(marks(woods)) == "hickory", ]
# }
# NOT RUN {
plot(h)
# }
```

*Documentation reproduced from package spatstat, version 1.61-0, License: GPL (>= 2)*