如何为每个用户 ID 的问题创建一个包含一系列答案（在不同时间）的新数据框

Question

I'm working on a dataframe with a lot of questions and some people answered several times to the inquiry. I would like to study the evolution of their answer.

I have a database that looks like:

User ID	Time	Answer
User A	2012-01	5
User B	2012-02	6
User B	2012-01	5
User B	2012-03	6
User A	2012-02	5
User C	2012-03	6

And I would like to have a dataframe with the answer of each user classed by time like that:

User ID	2012-01	2012-02	2012-03
User A	5	6	X
User B	5	5	X
User C	X	X	6

Do you know how I could do that?

I've tried to use group by user ID but it didn't work.

Answer 1

library(tidyr)

# Your data
df<-read.table(text="
User ID Time    Answer
User A  2012-01 5
User B  2012-02 6
User B  2012-01 5
User B  2012-03 6
User A  2012-02 5
User C  2012-03 6",
header=TRUE) 

df %>% 
  pivot_wider(names_from = Time,
              values_from=Answer)

# A tibble: 3 × 5
  User  ID    `2012-01` `2012-02` `2012-03`
  <chr> <chr>     <int>     <int>     <int>
1 User  A             5         5        NA
2 User  B             5         6         6
3 User  C            NA        NA         6