Plot: Looping over nested data - r

Question

I'm currently having an issue where I'm trying to nest simulated data for an efficient frontier inside a tibble containing all 250 simulations. The tibble will have 1 column named "sim" which indicates the number of the simulation, i.e. the rows in this column runs from 1:250. The other column should contain the nested simulation data which is a 3x123 tibble for each simulation. I've successfully, with help from a nice soul here, managed to create this tibble containing the efficient frontiers. Now I need to make a loop running through this tibble and plotting all of the 250 efficient frontiers in one plot.
I've tried to replicate the problem such that you don't need all of the previous code and data to see the issue. In this simple and reproducible example I have a table which is a 5x2 Tibble where the column 'sim' lists simulations (1:5) and 'obs' holds an individual 5x3 tibble with some coordinates:
library(tidyverse)
library(ggplot2)
counter = 0
table <- tibble(sim = 1:5, obs = NA)
for(i in (1:5)){
counter = counter + 1
tibble <- tibble(a = NA, b = 1:5, x = c(counter + 1), y = c(counter*2-1))
tibble$a <- counter
nested_tibble <- tibble %>% nest(data = -a) %>% select(-a)
table$obs[i] <- nested_tibble[[1]]
}
for (i in (1:5)){
print(ggplot()+
geom_point( data = (table %>% filter(sim == i) %>% .$obs)[[1]],
aes(x = x, y = y),
color = "red",
size = 4))
}
As mentioned I wish for it to plot all of the 5 coordinates in one plot such that I can replicate this to plot 250 efficient frontiers. However, when I run the code it only returns the last coordinate.
I hope my formulation makes sense. If you need any additional documentation please let me know.

Answer 1

I am not sure, but this should do the job. I think using lists is way better to store nested structure. So, the code below returns a list called table_out.
Please, have a look if this is what you want.
library(tibble)
library(data.table)
library(ggplot2)
N_sim <- 5
table_out <- vector("list", 5)
for ( i in seq_len(N_sim) ) {
current_table <- tibble(a = i, b = 1L:N_sim, x = i + 1, y = i*2 - 1)
table_out[[ i ]] <- current_table
}
# this creates a data.table (like a data.frame) from a list
final <- rbindlist( table_out )
ggplot(final, aes(x, y)) +
geom_point(color = "red", size = 4)
Created on 2021-03-03 by the reprex package (v1.0.0)