I am working on a project that assigns multiple ARIMA models to my data segmented by a grouping variable. Here is a reproducible example which runs as expected:
#Load libraries
library(dplyr)
library(workflows)
library(tidyr)
library(recipes)
library(parsnip)
library(tidymodels)
library(modeltime)
library(purrr)
#Set up data
df <- m750 %>%
mutate(year = lubridate::year(date)) %>%
filter(year>=2007 & year <=2009) %>%
select(c(-id))
#Nest data by year
df_nest <- df %>%
drop_na() %>%
nest(data_full = c(-year))
#Create recipes
rec_year_list <- list()
num_years <- length(unique(df$year))
for (i in 1:num_years){
rec_year_list[[i]] <- recipe(value ~ date, data = df_nest$data_full[[i]])
}
#Assign recipes to workflows
wfl_list <- workflow()
for (i in 1:num_years){
wfl_list[[i]] <- wfl_list %>%
add_recipe(rec_year_list[[i]]) %>%
add_model(
arima_reg() %>%
set_engine(engine='auto_arima')
)
}
#Assign workflows to data
df_nest <- df_nest %>%
mutate(workflow = case_when(year==2007 ~ list(wfl_list[[1]]),
year==2008 ~ list(wfl_list[[2]]),
year==2009 ~ list(wfl_list[[3]])
)
)
In this example, it's not a big deal to use the mutate and case_when functions since I only have 3 values of my grouping variable. However, in my actual data, I have many values for the grouping variable (ie: >3000). How could I rewrite this last chunk of code as a for loop to properly assign an element of wfl_list to the proper grouping variable as a value in a new column in df_nest.
Try
df_nest$workflow <- vector('list', nrow(df_nest))
for(i in seq_len(nrow(df_nest)))
df_nest$workflow[i] <- list(wfl_list[[i]])
-output
> df_nest
# A tibble: 3 × 3
year data_full workflow
<dbl> <list> <list>
1 2007 <tibble [12 × 2]> <workflow>
2 2008 <tibble [12 × 2]> <workflow>
3 2009 <tibble [12 × 2]> <workflow>