Admin
1
Use: seq(),rep()and possibly other commonly-used operators/functions,but NOT c()or any explicit loops to create the following sequences (compound expres-sions are allowed).
I have this sequence I wanted to create:
2.5 5.5 9.5 14.5 20.5 27.5 35.5
I know the increment is cumsum(3:8) but how do I put this into rep(seq(2.5, 35.5))? I tried:
rep(seq(2.5, 35.5, cumsum(3:8)))
but it gives me error. How do I do this? Thanks guys!
We need
c(2.5, 2.5 + cumsum(3:8))
[1] 2.5 5.5 9.5 14.5 20.5 27.5 35.5
or slightly more compact
2.5 + c(0, cumsum(3:8))
[1] 2.5 5.5 9.5 14.5 20.5 27.5 35.5
If we don't want any c, why not create a 0 vector and fill it
out <- numeric(7)
# or use rep
out <- rep(0, 7)
out[1] <- 2.5
out[-1] <- 2.5 + cumsum(3:8)
out
[1] 2.5 5.5 9.5 14.5 20.5 27.5 35.5
Or use replace
replace(rep(2.5, 7), -1, 2.5 + cumsum(3:8))
[1] 2.5 5.5 9.5 14.5 20.5 27.5 35.5
Or as @user20650 mentioned
rep(2.5, 7) + unlist(list(0, cumsum(seq(3, 8))))
[1] 2.5 5.5 9.5 14.5 20.5 27.5 35.5
Or use lag
library(dplyr)
lag(2.5 + cumsum(3:9), default = 2.5)
[1] 2.5 5.5 9.5 14.5 20.5 27.5 35.5
