If you want something that is fast, read the file in, strip off the
colon/data, write it out to a temp and then read it back in. Here is
a 355K line file:
> temp <- tempfile()
> input <- readLines('/temp/colon.txt')
> length(input)
[1] 355212
> system.time(input <- gsub("(:[0-9]+)", "", input))
user system elapsed
0.72 0.00 0.74
> head(input)
[1] "1 5 27 345" "1 5 27 345" "1 5 27 345" "1 5 27 345" "1
5 27 345" "1 5 27 345"
> writeLines(input, temp)
> system.time(newInput <- read.table(temp))
user system elapsed
1.08 0.02 1.13
> dim(newInput)
[1] 355212 4
>
> head(newInput)
V1 V2 V3 V4
1 1 5 27 345
2 1 5 27 345
3 1 5 27 345
4 1 5 27 345
5 1 5 27 345
6 1 5 27 345
On Tue, Oct 9, 2012 at 12:56 AM, Noah Silverman <noahsilver...@ucla.edu> wrote:
> I have a bunch of data sets that were created for the libsvm tool. They are
> in "colon separated sparse format".
>
> i.e.
>
> 1 5:1 27:3 345:10
>
> Is a row with the label of "1" and only has values in columns 5, 27, and 345.
>
> I want to read these into a data.frame in R.
>
> Is there a simple way to do this?
>
> --
> Noah Silverman, M.S.
> UCLA Department of Statistics
> 8117 Math Sciences Building
> Los Angeles, CA 90095
>
> ______________________________________________
> 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.
--
Jim Holtman
Data Munger Guru
What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.
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