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Dear all, If I have a data frame x<-data.frame(x1=c(1,7),x2=c(4,6),x3=c(8,2)): x1 x2 x3 1 4 8 7 6 2 I want to sort the whole data and get this: x1 1 x3 2 x2 4 x2 6 x1 7 x3 8 If I do sort(X), R reports: Error in order(list(x1 = c(1, 7), x2 = c(4, 6), x3 = c(8, 2)), decreasing = FALSE) : unimplemented type 'list' in 'orderVector1' The only way

Hi, netters, This is probably a rookie question but I couldn't find the answer after hours of searching and trying. Suppose there'a a dataframe M: x y 10 A 13 B 8 A 11 A I want to locate the rows where x >=10 and y="A". I know how to do it to vectors by using which, but how to do it with the dataframe? Thank you very much! Zhihua Li

Hi netters, Suppose I have two data frames X and Y. X has three colnames A, B and C. Y has three colnames A,B and D. I want to combine them into one matrix, joining the rows having the same A and B values (X$A==Y$A and X$B = Y$B). So the resulting dataframe has four variables/columns: A,B,C and D. I was wondering what's the best way to do it in R. Could anyone give me some advice? Thanks!

Hi, netters, First of all, thanks a lot for all the prompt replies to my earlier question about "merging" data frames in R. Actually that's an equivalence to the "join" clause in mysql. Now I have another question. Suppose I have a data frame X with lots of columns/variables: Name, Age,Group, Type, Salary. I wanna do a subtotal of salaries: aggregate(X$Salary,

Hi, R-users, If I have a data frame like this: >x<-data.frame(g=c("g1","g2","g1","g1","g2"),v=c(1,7,3,2,8)) g v 1 g1 1 2 g2 7 3 g1 3 4 g1 2 5 g2 8 It contains two groups, g1 and g2. Now for each group I want the max v: > aggregate(x$v,list(g=x$g),max) g x 1 g1 3 2 g2 8 Beautiful. But what if I want to keep the row index of (g1

Dear netters, suppose I have a matrix X [1,] 'c1' 'r6' '150'[2,] 'c1' 'r4' '70'[3,] 'c1' 'r2' '20'[4,] 'c1' 'r5' '90'[5,] 'c2' 'r2' '20'[6,] 'c3' 'r1' '10'I want to apply some funciton to groups of rows by the first column.If the function is just to