This is an offshoot of my previous query on substituting simulated variables using rnorm().
Now, I'm faced with another tricky thing to navigate since I'm a very beginner in R. Say:
# Values representing the number of simulations for each observation
simulations <- c(728, 680, 631, 583, 534, 486, 437, 388, 340, 291)
# Use lappy to generate the series of simulations for each observation
unit.cost <- lapply(simulations, rnorm, mean = 8403.86, sd = 1000)
bldg.size <- lapply(simulations, rnorm, mean = 35, sd = 5)
Considering that the mean and sd are constant for unit.cost and bldg.size, how do I multiply the simulated variables against each other for EACH observation, returning a list of the product (multiplied variables). For example, on the first observation, there will be 728 simulations of unit.cost and 728 simulations of bldg.size. I want these simulations be multiplied against each other, in order, to come up with a new variable called "bldg.cost" representing the product.
I'm also expecting to generate the sum of "bldg.cost" for each observation. In the end, I should have a data frame reflecting the sum of "bldg.cost" for each observation.
You can use Map
Map(function(x,y) x * y, unit.cost, bldg.size)
library(tidyverse)
bldg <- tibble(
simulations,
unit.cost = lapply(simulations, rnorm, mean = 8403.86, sd = 1000),
bldg.size = lapply(simulations, rnorm, mean = 35, sd = 5),
bldg.cost = Map(function(x,y) x * y, unit.cost, bldg.size),
) |>
unnest(cols=c(unit.cost, bldg.size, bldg.cost))
summarise(bldg, sum=sum(bldg.cost), .by=simulations)