Flatten List Columns into a Wide or Long Form

Source: R/col_flatten.R

Converts list columns into separate columns or into a long form.

col_flatten(indt, cols, drop = FALSE)

col_flattenLong(indt, cols)

Arguments

indt

The input data.table.
cols

Character vector containing the names of list columns
drop

Logical. Should the list columns be dropped from the original data.table?

Value

A data.table.

References

http://stackoverflow.com/q/34206003/1270695

Author

Ananda Mahto

Examples


df <- structure(
  list(CAT = structure(1:2, .Label = c("A", "B"), class = "factor"),
       COUNT = list(1:3, 4:5), TREAT = list(c("Treat-a", "Treat-b"), 
       c("Treat-c", "Treat-d", "Treat-e"))), 
       .Names = c("CAT", "COUNT", "TREAT"), 
       row.names = c(NA, -2L), class = "data.frame")
       
col_flatten(df, c("COUNT", "TREAT"), TRUE)
#>    CAT COUNT_1 COUNT_2 COUNT_3 TREAT_1 TREAT_2 TREAT_3
#> 1:   A       1       2       3 Treat-a Treat-b    <NA>
#> 2:   B       4       5      NA Treat-c Treat-d Treat-e


col_flattenLong(df, c("COUNT", "TREAT"))
#>    CAT variable COUNT   TREAT
#> 1:   A        1     1 Treat-a
#> 2:   A        2     2 Treat-b
#> 3:   A        3     3    <NA>
#> 4:   B        1     4 Treat-c
#> 5:   B        2     5 Treat-d
#> 6:   B        3    NA Treat-e