[R] How can I merge data with differing length?

[Kuma Raj]

How can I merge  data frame df and "tem" shown below by filling the
head of "tem"  with missing values?


a<- rnorm(1825, 20)
b<- rnorm(1825, 30)
date<-seq(as.Date("2000/1/1"), by = "day", length.out = 1825)

df<-data.frame(date,a,b)


tem<- rpois(1095,  lambda=21)

Thanks