Apply a function cumulatively to a list of matrices or numbers

FUN must be a binary function that also accepts a single argument. The result is a list with first element FUN(a[[1]]). For i >= 2, elements are FUN(a[[i]], out[[i-1]]), where out is the result list.

Usage

cumapply_byname(FUN, a)

Arguments

FUN

the function to be applied

a

the list of matrices or numbers to which FUN will be applied cumulatively

Value

a list of same length as a

containing the cumulative application of FUN to a

Details

naryapply_byname() and cumapply_byname() are similar. Their differences can be described by considering a data frame. naryapply_byname() applies FUN to several columns (variables) of the data frame. For example, sum_byname() applied to several variables gives another column containing the sums across each row of the data frame. cumapply_byname() applies FUN to successive entries in a single column. For example sum_byname() applied to a single column gives the sum of all numbers in that column.

Examples

cumapply_byname(sum, list(1, 2, 3, 4))
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 3
#> 
#> [[3]]
#> [1] 6
#> 
#> [[4]]
#> [1] 10
#> 
cumapply_byname(sum_byname, list(1, 2, 3, 4))
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 3
#> 
#> [[3]]
#> [1] 6
#> 
#> [[4]]
#> [1] 10
#> 
cumapply_byname(prod, list(1, 2, 3, 4))
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 2
#> 
#> [[3]]
#> [1] 6
#> 
#> [[4]]
#> [1] 24
#> 
cumapply_byname(hadamardproduct_byname, list(1, 2, 3, 4))
#> [[1]]
#> [1] 1
#> 
#> [[2]]
#> [1] 2
#> 
#> [[3]]
#> [1] 6
#> 
#> [[4]]
#> [1] 24
#>