如何在R中的小标题中将列表列转换为向量

Question

I am trying to collapse the Weeks column in the tibble (called data) below so that the result is a tibble with two columns: 1 for weeks and another for associated values. Since the weeks column is a list, I am not sure how to do it. Could you please help?

> head(data)
# A tibble: 6 x 1
  ``$Weeks   $Value
  <list>      <dbl>
1 <date [9]>     30
2 <date [3]>     20
3 <date [3]>     15
4 <date [5]>     10
5 <date [2]>      9
6 <date [9]>      5

desired result would look like:

      $Weeks   $Value
      <Date>      <dbl>
 1  "2019-01-01     30
 2  "2019-01-08     30
 3  "2019-01-15     30
 etc..

Current Structure:

  > str(data)
List of 1
 $ :Classes ‘tbl_df’, ‘tbl’ and 'data.frame':   7 obs. of  2 variables:
  ..$ Weeks:List of 7
  .. ..$ : Date[1:9], format: "2018-11-11" "2018-11-18" "2018-11-25" "2018-12-02" ...
  .. ..$ : Date[1:3], format: "2018-12-02" "2018-12-09" "2018-12-16"
  .. ..$ : Date[1:3], format: "2018-12-23" "2018-12-30" "2019-01-06"
  .. ..$ : Date[1:5], format: "2018-11-04" "2018-11-11" "2018-11-18" "2018-11-25" ...
  .. ..$ : Date[1:2], format: "2018-11-25" "2018-12-02"
  .. ..$ : Date[1:9], format: "2018-11-18" "2018-11-25" "2018-12-02" "2018-12-09" ...
  .. ..$ : Date[1:14], format: "2018-09-30" "2018-10-07" "2018-10-14" "2018-10-21" ...
  ..$ Value: num [1:7] 30 20 15 10 9 5 6

dput(data)

> dput(data)
list(structure(list(Weeks = list(structure(c(17846, 17853, 17860, 
17867, 17874, 17881, 17888, 17895, 17902), class = "Date"), structure(c(17867, 
17874, 17881), class = "Date"), structure(c(17888, 17895, 17902
), class = "Date"), structure(c(17839, 17846, 17853, 17860, 17867
), class = "Date"), structure(c(17860, 17867), class = "Date"), 
    structure(c(17853, 17860, 17867, 17874, 17881, 17888, 17895, 
    17902, 17909), class = "Date"), structure(c(17804, 17811, 
    17818, 17825, 17832, 17839, 17846, 17853, 17860, 17867, 17874, 
    17881, 17888, 17895), class = "Date")), Value = c(30, 20, 
15, 10, 9, 5, 6)), row.names = c(NA, -7L), class = c("tbl_df", 
"tbl", "data.frame")))

Answer 1

Edited Answer

Ok, so your original data is stored as a list, which doesn't allow the unnest() function to behave as expected. We'll need to extract the element first. Then, because your list-column is itself a list of lists, we'll have to use map to extract out what we want. The solution below solves this problem, and gives you what you want.

  > data[[1]] %>%
      mutate(Weeks = map(Weeks, ~ tibble(Weeks =.x))) %>%
      unnest()

Output:

  # A tibble: 45 x 2
    Value Weeks     
    <dbl> <date>    
  1    30 2018-11-11
  2    30 2018-11-18
  3    30 2018-11-25
  4    30 2018-12-02
  5    30 2018-12-09
  6    30 2018-12-16
  7    30 2018-12-23
  8    30 2018-12-30
  9    30 2019-01-06
 10    20 2018-12-02

Original Answer:

As akrun said in the comments, you can just do unnest(data, Weeks) .