group_rows in a for-loop to create a table

Question

Here is the code for my example-data:

library(tidyverse)
library(kableExtra)
library(knitr)

df1 <- tibble(
var1A= rnorm(1:10) +1,
var1B= rnorm(1:10) +1,
var2A= rnorm(1:10) +2,
var2B= rnorm(1:10) +2,
var3A= rnorm(1:10) +3,
var3B= rnorm(1:10) +3)


df2 <- tibble(
var1A= rnorm(1:10) +1,
var1B= rnorm(1:10) +1,
var2A= rnorm(1:10) +2,
var2B= rnorm(1:10) +2,
var3A= rnorm(1:10) +3,
var3B= rnorm(1:10) +3)


df3 <- tibble(
var1A= rnorm(1:10) +1,
var1B= rnorm(1:10) +1,
var2A= rnorm(1:10) +2,
var2B= rnorm(1:10) +2,
var3A= rnorm(1:10) +3,
var3B= rnorm(1:10) +3)

I have 3 dataframes with 2 variables (A and B) ant every df has 3 thresholds (1,2,3). Now I want to perform a t.Test for every df and every threshold -> t.test(varA, varB) .

With ths code I get what I want: a table of t.tests for all dfs and all thresholds.

threshold <- seq(1,3)
list_dfs = c('df1','df2','df3')

table.t.test <-map(list_dfs,
               function(df_name){
                 x <- get(df_name)
                 lapply(threshold, function(i){
                   t.test(x %>%
                            pull(paste0("var",i,"A")), 
                          x %>% 
                            pull(paste0("var",i,"B")))
                 }) %>% 
                   map_df(broom::tidy) %>% 
                   add_column(.before = 'estimate',
                              df = df_name, 
                              threshold = thresholds)
               }) %>% 
do.call(rbind, .)%>%
select(-estimate, -parameter, -conf.low, -conf.high, -method, -alternative)

In the last step I want to group the rows by the dataframes in the table:

table.t.test%>%
kable()%>%
kable_styling()%>%
group_rows(list_dfs[1],1,3)%>%
group_rows(list_dfs[2],4,6)%>%
group_rows(list_dfs[3],7,9)

My concern is that I want to group the rows automatically with a for-loop:

for (i in seq_along(list_dfs)){
table.t.test%>%
kable()%>%
kable_styling()%>%
group_rows(list_dfs[i],i*3-2,i*3)
}

But my for-loop doesn't work. Can someone help my to implement the group_rows()-function in the for-loop?

Answer 1

If I understand correctly, I think you can skip the for-loop and just use the index = argument of group_rows . Something like this (below). Also, in you sample code I think you flipped threshold = thresholds when adding a new column.

names <- sapply(list_dfs, "[")
frequencies <- rle(table.t.test$df)$lengths

table.t.test[-1] %>% # [-1] b/c redundant info if you are grouping rows
  kable()%>%
  kable_styling()%>%
  group_rows(index = setNames(frequencies, names))