similar to: getting column names of row-by-row sorted matrix

Hello R users, Here is my question about generating random sample. How to set the random seed to recreate the same random numbers? For example, 10 random numbers is generated from N(0,1), then "runif(10)" is used.What if I want to get the same 10 random numbers when I run runif(10) again? Is it possible?I think .Random.seed should be used here. Thanks. Xiaoxi [[alternative

Hi all. I'm looking for robust ways of building lagged variables in a dataset with multiple individuals. Consider a dataset with variables like the following: ## set.seed(123) d <- data.frame(id = rep(1:2, each=3), time=rep(1:3, 2), value=rnorm(6)) ## >d id time value 1 1 1 -0.56047565 2 1 2 -0.23017749 3 1 3 1.55870831 4 2 1 0.07050839 5 2 2 0.12928774 6

Once again I need to tap into the collective knowledge here. Let's say I have the following columns and data below Y X1 X2 X3 X4 I would like to generate additional new columns and column names (ie the data would be squared - and I'd like the column names to reflect this) like: Y X1 X2 X3 X4 X1^2 X2^2 X3^2 X4^2 I believe I can compute the values correctly with the code below, but I

Sorry, another newbie question :-( I loaded a data set with 10 rows and 30 columns. The first column is characters for names of car manufacturers: Jeep Nissan Toyota1 Toyota2 Etc. How can I replace "Toyota2" with "Scion"? Thanks again [[alternative HTML version deleted]]

I am writing a function where the arguments are names of objects or variable names in a data frame. To convert the strings to the objects I am using eval(parse(text=name)): f.graph.two.vbs<-function(dataname,v1){ val<-paste(dataname,v1,sep="$") val<-eval(parse(text=val)) val } However running this returns an error:

Hi @ all, how do I get the largest or lowest k values of list? It must similar to the min() / max() function, but I just don't get it. Best wishes, Markus