I have a data frame named "database" with panel data, a little piece of which looks like this:
Symbol Name Trial Factor1 Factor2 External 1 548140 A 1 -3.87 -0.32 0.01 2 547400 B 1 12.11 -0.68 0.40 3 547173 C 1 4.50 0.71 -1.36 4 546832 D 1 2.59 0.00 0.09 5 548140 A 2 2.41 0.50 -1.04 6 547400 B 2 1.87 0.32 0.39 What I want to do is to calculate correlation between each factor and external for each Symbol, and record the corr. estimate, the p.value, the name and number of observations in a vector named "vector", then rbind these vectors together in "results". When there are fewer than 5 observations for a particular symbol I want to put NAs in each column of "vector". I tried with the following code, making assumption that by splits database into sort of smaller dataframes for each Symbol (that's the "x"): factor.names <- c("Factor1", "Factor2") factor.pvalue <- c("SigF1", "SigF2") results <- numeric() vector <- matrix(0, ncol=(length(factor.names)*2+2), nrow=1) colnames(vector) <- c("No.obs", factor.names, factor.pvalue) application <- function(x){ rownames(vector) <- x$Name for(i in 1:length(factor.names)){ if(dim(x)[1]>=5){ vector[1] <- dim(x)[1] vector[i+1] <- cor.test(x$External, x[,factor.names[i]], method="kendall")$estimate vector[i+3] <- cor.test(x$External, x[,factor.names[i]], method="kendall")$p.value } else { vector <- rep(NA, length(vector)) } } results <- rbind(results, vector) } by(database, database$Symbol, application) This did not work. I get : "Error in dimnames(x) <- dn : length of 'dimnames' [1] not equal to array extent" I used browser() and I see that the Name is not assigned to the row name of vector and then dim(x)[1] does not work. What am I doing wrong? Do not understand. :-( Thank you in advance for your help. Regards, JM -- Jonas Malmros Stockholm University Stockholm, Sweden ______________________________________________ R-help@r-project.org mailing list 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.