Apply a function to an element of a matrix specified by rows and columns

FUN is applied to the element of a that is specified by row and col.

Usage

elementapply_byname(FUN, a, row, col, .FUNdots = NULL)

Arguments

FUN

a unary function to be applied to specified rows and columns of a

a

the argument to FUN

row

the row name of the element to which FUN will be applied

col

the column name of the element to which FUN will be applied

.FUNdots

a list of additional arguments to FUN. (Default is NULL.)

Value

a, after FUN has been applied to the element at row and col

Details

row and col can be any of row or column names or integer indices or a mix of both.

Examples

divide <- function(x, divisor){
  x/divisor
}
m <- matrix(c(1:4), nrow = 2, ncol = 2, dimnames = list(c("r1", "r2"), c("c1", "c2"))) %>% 
  setrowtype("row") %>% setcoltype("col")
elementapply_byname(divide, a = m, row = 1, col = 1, .FUNdots = list(divisor = 2))
#>     c1 c2
#> r1 0.5  3
#> r2 2.0  4
#> attr(,"rowtype")
#> [1] "row"
#> attr(,"coltype")
#> [1] "col"
elementapply_byname(divide, a = m, row = 1, col = 2, .FUNdots = list(divisor = 10))
#>    c1  c2
#> r1  1 0.3
#> r2  2 4.0
#> attr(,"rowtype")
#> [1] "row"
#> attr(,"coltype")
#> [1] "col"
elementapply_byname(divide, a = m, row = "r2", col = "c2", .FUNdots = list(divisor = 100))
#>    c1   c2
#> r1  1 3.00
#> r2  2 0.04
#> attr(,"rowtype")
#> [1] "row"
#> attr(,"coltype")
#> [1] "col"