[R] Split a dataframe by rownames and/or colnames

[Tim Richter-Heitmann]

Dear List,

Consider this example

df <- data.frame(matrix(rnorm(9*9), ncol=9))
names(df) <- c("c_1", "d_1", "e_1", "a_p", "b_p", "c_p", "1_o1", "2_o1", 
"3_o1")
row.names(df) <- names(df)


indx <- gsub(".*_", "", names(df))

I can split the dataframe by the index that is given in the column.names 
after the underscore "_".

list2env(
   setNames(
     lapply(split(colnames(df), indx), function(x) df[x]),
     paste('df', sort(unique(indx)), sep="_")),
   envir=.GlobalEnv)

However, i changed my mind and want to do it now by rownames. Exchanging 
colnames with rownames does not work, it gives the exact same output (9 
rows x 3 columns). I could do
as.data.frame(t(df_x),
but maybe that is not elegant.
What would be the solution for splitting the dataframe by rows?

Thank you very much!

-- 
Tim Richter-Heitmann