How can I "transpose" the data in this way with R studio?

Question

Hi I have a dataframe similar to the one in the photo (left one) and I'm trying to obtain the format on the right one. How can I do it?

example dataset and what I would like to obtain

I know that is a stupid question, but I'm missing something..

How can I obtain that result? thank you very much!

I tried those one

long_data <- melt(data,id=c("Test"))

data.long <- data %>% pivot_longer(-Test, names_to = "variables", values_to = "value")

I also tried just

data_long=t(data)

Answer 1

library(dplyr)
library(tidyr)

df %>% 
  pivot_longer(-Test) %>% 
  pivot_wider(names_from = Test, values_from = value) 

 name  Pre       Post     
  <chr> <list>    <list>   
1 Q1    <dbl [4]> <dbl [4]>
2 Q2    <dbl [4]> <dbl [4]>
3 Q3    <dbl [4]> <dbl [4]>

or

library(dplyr)
library(tidyr)

df %>% 
  pivot_longer(-Test) %>% 
  pivot_wider(names_from = Test, values_from = value) %>% 
  unnest()

name    Pre  Post
   <chr> <dbl> <dbl>
 1 Q1        2     3
 2 Q1        2     2
 3 Q1        1     3
 4 Q1        3     2
 5 Q2        3     2
 6 Q2        3     3
 7 Q2        5     4
 8 Q2        4     2
 9 Q3        4     3
10 Q3        2     4
11 Q3        2     5
12 Q3        3     3

OR

library(dplyr) #>= 1.1.0
library(tidyr)

df %>% 
  pivot_longer(-Test) %>% 
  pivot_wider(names_from = Test, values_from = value) %>% 
  unnest() %>% 
  summarize(mean_pre = mean(Pre), mean_post = mean(Post), .by=name)

  name  mean_pre mean_post
  <chr>    <dbl>     <dbl>
1 Q1        2         2.5 
2 Q2        3.75      2.75
3 Q3        2.75      3.75

data:

df <- structure(list(Test = c("Pre", "Pre", "Pre", "Pre", "Post", "Post", 
"Post", "Post"), Q1 = c(2, 2, 1, 3, 3, 2, 3, 2), Q2 = c(3, 3, 
5, 4, 2, 3, 4, 2), Q3 = c(4, 2, 2, 3, 3, 4, 5, 3)), class = c("tbl_df", 
"tbl", "data.frame"), row.names = c(NA, -8L))