Select every nth row from dataframe

Question

I have a data table and want to extract every fifth row from it to create a new table. Is there a command to achieve this?

Here is an sample of my data:

Answer 1

If you want to extract 5,10...

newdf <- df[c(rep(FALSE,4),TRUE), ]

If 1,6,11,

newdf <- df[c(TRUE,rep(FALSE,4)), ]