Adding a new value into a nested list in R - r

Question

I am using Highcharts for visualization and Highcharter generates charts as a nested list similar to the example_list below. I'm summarizing it here because the original list is much longer and complex.
example_list <- list(
x = list(
hc_opts = list(
series = list(
list(group = "group_a", data = list(0,2,4,6)),
list(group = "group_b", data = list(0,3,6,9)),
list(group = "group_c", data = list(9,4,8,12))))))
Just like the group and data nodes, I would like to add an element called type at the level of group and data, but only to the 1st and 3rd elements under series. I'm basically looking for an output same as the following:
example_list <- list(
x = list(
hc_opts = list(
series = list(
list(group = "group_a", data = list(0,2,4,6), type = "type_X"),
list(group = "group_b", data = list(0,3,6,9)),
list(group = "group_c", data = list(9,4,8,12), type = "type_Y")))))
I can do this with a for-loop (because I have vectors for locations and types), but
there should be an elegant way of coding it. My best attempt so far.
locations <- c(1,3)
types <- c("type_X","type_Y")
for(i in 1:length(locations)) {
example_list[["x"]][["hc_opts"]][["series"]][[locations[i]]][["type"]] <- types[i]
}

Answer 1

We can use Map :
example_list$x$hc_opts$series[c(1, 3)] <- Map(c,
example_list$x$hc_opts$series[c(1, 3)], type = types)
#$x
#$x$hc_opts
#$x$hc_opts$series
#$x$hc_opts$series[[1]]
#$x$hc_opts$series[[1]]$group
#[1] "group_a"
#$x$hc_opts$series[[1]]$data
#$x$hc_opts$series[[1]]$data[[1]]
#[1] 0
#$x$hc_opts$series[[1]]$data[[2]]
#[1] 2
#$x$hc_opts$series[[1]]$data[[3]]
#[1] 4
#$x$hc_opts$series[[1]]$data[[4]]
#[1] 6
#$x$hc_opts$series[[1]]$type
#[1] "type_X"
#...
#...