Splitting a data frame into equal parts

You could use split(), with rep() to create the groupings.

n <- 10
nr <- nrow(df)
split(df, rep(1:ceiling(nr/n), each=n, length.out=nr))

This can be solved with nesting using tidyr/dplyr

require(dplyr) 
require(tidyr)

num_groups = 10

iris %>% 
   group_by((row_number()-1) %/% (n()/num_groups)) %>%
   nest %>% pull(data)