How to copy row from one data.frame in to another [R]
Your example happens to pretty much answer your question. (Try it out!)
If, instead of replacing a row in the target data.frame, you want to add a row to it, try rbind() instead:
X <- data.frame(name=LETTERS[1:3], value=1:3, stringsAsFactors=FALSE)Y <- data.frame(name=letters[1:3], value=rnorm(3), stringsAsFactors=FALSE)X[1,] <- Y[1,]X <- rbind(X, Y[3,])