I want to create a list of lists, and this list will be filled by calls to various functions. The output is awkward and unworkabe, so there must be a better way than the one I used. Here is a simplified code to illustrate the idea
choices <- list()
###############
add_wealth <- function(ch, wealth) {
a <- list(type="wealth", parameter =wealth)
list(ch, a)
}
wealth <- 1
choices <- add_wealth(choices, wealth)
##############
add_diversification <- function(ch, div) {
a <- list(type="diversification", parameter =div)
list(ch, a)
}
div <- .7
choices <- add_diversification(choices, div)
##############
add_margin <- function(ch, bounds) {
a <- list(type="margin", parameter=bounds)
list(ch, a)
}
bounds <- c(1, 3)
choices <- add_margin(choices, bounds)
choices
Ideally, here is the output I need (or something close enough)
[[1]]
[[1]]$type
[1] "wealth"
[[1]]$parameter
[1] 1
[[2]]
[[2]]$type
[1] "diversification"
[[2]]$parameter
[1] .7
[[3]]
[[3]]$type
[1] "margin"
[[3]]$parameter
[1] 1 3
How to create a function to add a list to an existing list of list?
If there already is an (empty) list L, i.e.,
L = list()
we can simply do
L = append(L, list(list(type='wealth', parameter=1))) |>
append(list(list(type='diversification', parameter=.7)))
> L List of 2 $ :List of 2 ..$ type : chr "wealth" ..$ parameter: num 1 $ :List of 2 ..$ type : chr "diversification" ..$ parameter: num 0.7
i.e.,
add2list = \(l, ty, pa) append(l, list(list(type=ty, parameter=pa)))
> add2list(L, "margin", c(1, 2)) [[1]] [[1]]$type [1] "wealth" [[1]]$parameter [1] 1 [[2]] [[2]]$type [1] "diversification" [[2]]$parameter [1] 0.7 [[3]] [[3]]$type [1] "margin" [[3]]$parameter [1] 1 2