CODEWITHSUNDEEP
rsplit
Steve
Steve

Reputation: 333

In R, how to reverse a split()

In R, once the following code is ran:

temp <- split(mtcars, mtcars$cyl)

If I send only "temp" to someone else ...

What code can he use to put back slices of "temp" together? He does not need to use "cyl" as column name; he can use whatever he wants. Thanks!

Upvotes: 2

Views: 1984

Answers (2)

Ronak Shah
Ronak Shah

Reputation: 388962

You can use dplyr's bind_rows or data.table's rbindlist. To identify which rows come from which element of the list we can use .id/idcol parameter.

dplyr::bind_rows(temp, .id = 'id')
data.table::rbindlist(temp, idcol = 'id')

By default it assigns name of the list as id column, if you want them as numbers you can remove the names from the list using unname.

dplyr::bind_rows(unname(temp), .id = 'id')
data.table::rbindlist(unname(temp), idcol = 'id')

Upvotes: 0

akrun
akrun

Reputation: 887068

We can use do.call with rbind, but the order or rows may be different

do.call(rbind, temp)

If the column info is known, then unsplit can be useful as it will keep the same order as before the split

unsplit(temp, mtcars$cyl)

Upvotes: 7

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