Extract certain parts of nested lists of a list to create a dataframe

Below I apply shapiro test on the first 4 columns of iris dataset. I would like to create a dataframe out of this with the column name, the p value and the w score.

apply(iris,2,shapiro.test)

>Solution :

You can do this:

df <- apply(iris[,1:4], 2, function(x) {
  sh <- shapiro.test(x)
  c(p = sh$p.value, sh$statistic)})

  Sepal.Length Sepal.Width Petal.Length  Petal.Width
p   0.01018116   0.1011543 7.412263e-10 1.680465e-08
W   0.97609027   0.9849179 8.762681e-01 9.018349e-01

You can make it tidy dataframe as follow:

library(tidyverse)
as.data.frame(df) %>% 
  rownames_to_column(var = "stats") %>% 
  pivot_longer(cols = -stats)

# A tibble: 8 x 3
  stats name            value
  <chr> <chr>           <dbl>
1 p     Sepal.Length 1.02e- 2
2 p     Sepal.Width  1.01e- 1
3 p     Petal.Length 7.41e-10
4 p     Petal.Width  1.68e- 8
5 W     Sepal.Length 9.76e- 1
6 W     Sepal.Width  9.85e- 1
7 W     Petal.Length 8.76e- 1
8 W     Petal.Width  9.02e- 1