How can I repeat a data.frame?

Question

It\'s easy to repeat a data.frame once,

mt2 <- rbind(mtcars, mtcars)

But what\'s an R-like way to do this generally? If I want 10 copies

Answer 1

If you can tolerate another package:

require(mefa)
rep(mtcars,10)

• works after all!

It appears a little faster:

system.time(mtcars[rep(1:nrow(mtcars),1e5),])
system.time(mtcars[rep(seq_len(nrow(mtcars)),1e5),])
system.time(rep(mtcars,1e5))

Gives:

 user  system elapsed 
 17.41    0.19   17.89
 17.11    0.31   17.91
 6.79    0.70    7.67

Caveats: 1) rep will not reproduce the row names; this is a separate step. 2) mefa::rep(mtcars,10) doesn't work as: Error: 'rep' is not an exported object from 'namespace:mefa'. Also mefa:::rep(mtcars,10) gives object 'rep' not found. Not sure why this is...