search for: coulum

Hello, There: I read data from tab-delimted text file(1888.txt) in C:/temp, which has thousands rows and 80 colulms, using read.delim("C:/temp/1888.txt"). when I retrieved the numeric coulum which has real zero values and applies R buid-in function such as mean( ), sum() and got a result of NA. It seems that R (R 1.6.2 in windows) considers zero as missing value (NA). Thus my question is how to read the real zero as zero. Thank in advance. Joshua

HI All, I have a data frame such as: > test x y p d [1,] 1 0 10 21 0 [2,] 2 3 11 12 0 [3,] 3 4 12 23 0 [4,] 3 5 13 24 0 and I want to perfor some operations on the first two coulums, conditional on the uneqaulity values on the 3rd and 4th columns. For instance: j = 3 test[test[,1] == j, 5] = test[test[,1] == j,2] + test[test[,2] == j,1] gives me the result: test: x y p d [1,] 1 0 10 21 0 [2,] 2 3 11 12 0 [3,] 3 4 12 23 6 [4,] 3 5 13 24 7 My probblem is the follo...