Dear all, I have a data.frame that includes a series of demographic variables for a set of respondents plus a dependent variable (Theta). For example:
Age Education Marital Familysize Income Housing Theta 1: 50 Associate degree Divorced 4 70K+ Owned with mortgage 9.147777 2: 65 Bachelor degree Married 1 10-15K Owned without mortgage 7.345036 3: 33 Bachelor degree Married 2 30-40K Owned with mortgage 7.974937 4: 69 Bachelor degree Never married 1 70K+ Owned with mortgage 7.733053 5: 54 Some college, less than college graduate Never married 3 30-40K Rented 7.648642 6: 35 Associate degree Separated 2 10-15K Rented 7.496411 My objective is to calculate the average of Theta across all pairs of two demographics. For 1 demographic this is straightforward: Demo_names <- c("Age", "Education", "Marital", "Familysize", "Income", "Housing") means1 <- as.list(rep(0, length(Demo_names))) for (i in 1:length(Demo_names)) { Demo_tmp <- Demo_names[i] means1[[i]] <- data_tmp[,list(mean(Theta)),by=Demo_tmp]} Is there an easy way to extent this logic to more than 1 variable? I know how to do this manually, e.g., data_tmp[,list(mean(Theta)),by=list(Marital, Education)] But I don't know how to integrate this into a loop. Thanks, Michael [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.