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I'm curious how to pivot a long data frame wide specifically using the {collapse} package. I like the performance aspect of the package, but I'm finding it hard to use at times for more mid-level data manipulation (e.g., tidyr::pivot_wider() )

An example would be taking this tibble:

tbl <- tibble::tibble(
    user_id = rep(1:3, each = 5),
    a =  rep(paste0("item", 1:5), times = 3),
    b =  sample(rnorm(1000), 15)
)

# A tibble: 15 x 3
   user_id a            b
     <int> <chr>    <dbl>
 1       1 item1  0.474  
 2       1 item2  0.658  
 3       1 item3 -0.609  
 4       1 item4 -0.710  
 5       1 item5 -0.936  
 6       2 item1 -1.06   
 7       2 item2 -0.307  
 8       2 item3 -1.69   
 9       2 item4  0.669  
10       2 item5  0.776  
11       3 item1 -0.00244
12       3 item2  1.33   
13       3 item3 -0.724  
14       3 item4 -0.646  
15       3 item5  1.69

And turning it into this using {collapse}:

tbl |> tidyr::pivot_wider(names_from="a", values_from="b")

# A tibble: 3 x 6
  user_id  item1  item2  item3 item4   item5
    <int>  <dbl>  <dbl>  <dbl> <dbl>   <dbl>
1       1 -0.597  0.672 -0.396 1.44  -0.419 
2       2  1.56   0.488 -0.980 0.648 -0.0903
3       3 -0.885 -0.675  0.376 1.02  -0.180
Maël
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sebelly
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  • I don't think `collapse` has a function for this. Have you looked at `dcast` from the `data.table` package, which offers performant pivoting? – Allan Cameron May 17 '22 at 13:13
  • Based on what @AllanCameron suggested. `data.table::dcast(as.data.table(tbl), user_id ~ a)` might help with time/speed. – Death Metal May 17 '22 at 13:40

0 Answers0