Spreading a two column data frame with tidyr

Question

I have a data frame that looks like this:

  a b
1 x 8
2 x 6
3 y 3
4 y 4
5 z 5
6 z 6

and I want to turn it into this:

  x y          


        

Answer 1

Since tidyr 1.0.0 you can use pivot_wider(), and because a doesn't have unique values you'll need a call to unchop on top :

library(tidyr)
df <- data.frame(
  a = c("x", "x", "y", "y", "z", "z"),
  b = c(8, 6, 3, 4, 5, 6)
)

pivot_wider(df, names_from = "a", values_from = "b", values_fn = list(b = list)) %>%
  unchop(everything())
#> # A tibble: 2 x 3
#>       x     y     z
#>     
#> 1     8     3     5
#> 2     6     4     6

^{Created on 2019-09-14 by the reprex package (v0.3.0)}