※ 引述《mapleV (Sucks)》之铭言：
: ※ 引述《untitled (Causality)》之铭言：
: : !!! How's the CPU of your computer?
: PIII 733Mhz for executing the transformation from loaded data to
: matrix. 3x seconds.
: Loading data takes 8~10 seconds.
: : Would you like to share your code with us next Monday?
: I think it's not necessary to show my code next Monday.
: My code is customized for usps data. Not very general.
: Just a simple idea.
: If there exists any errors, please remark it.
: load_transform <- function(filename , ncolumn)
: {
: mdt <- readLines(filename)
: temp <- list()
: for (i in 1: length(mdt))
: temp[[i]] <- as.numeric(matrix(strsplit(mdt[i], " |:")[[1]][2*c(1:ncolumn)-1]))
: dx <- matrix(,ncol = ncolumn ,nrow = length(mdt))
: for (i in 1:length(mdt))
: dx[i,] <- temp[[i]]
: dx
: }
I did some modify to the above code for index support. It takes
3x sec on 1.2G AMD CPU for usps loading. But I don't think it's fast
enough for hw3 still XD. Is there any other way? (any code problem please
tell me, thanks)
readData <- function (filename, ncolumn){
lines <- readLines(filename)
linenum <- length(lines)
valueIndex <- 2*(1:ncolumn)-1
indexIndex <- 2*(1:ncolumn-1)
dataMatrix <- matrix(0,linenum, ncolumn)
for(i in 1:linenum){
tmp <- as.numeric(matrix(strsplit(lines[i], " +|:", perl=TRUE)[[1]]))
dataTmp <- tmp[valueIndex]
indexTmp <- tmp[indexIndex]
iUsedIndex <- !is.na(indexTmp)
dUsedIndex <- !is.na(dataTmp)
dataMatrix[i, c(1, 1+indexTmp[iUsedIndex])] <- dataTmp[dUsedIndex]
}
return(dataMatrix)
}
tmp <- readData("usps", 257)