Hi Robert,

You might try

do.call(rbind, lapply(yourlist, "[", 1:4))

and then write the resulting file using write.table(...).

Best,
Jorge

On Sun, Feb 20, 2011 at 11:13 AM, Robert Baer <> wrote:

> ls is a list of character vectors created by strsplit()
>
> I want to concatenate  the 1st 4 character elements of each list item as a
> new vector called file.  I admit to being confused about list syntax even
> after numerous readings.
>
> Here's what I tried:
>
> ls <- list(c("Focused", "10k", "A12", "t04.tif", "+", "µm"), c("Focused",
> "10k", "A12", "t08.tif", "+", "µm"), c("Focused", "10k", "A12",
> "t12.tif", "+", "µm"), c("Focused", "10k", "A12", "t16.tif",
> "+", "µm"), c("Focused", "10k", "A12", "t20.tif", "+", "µm"),
>    c("Focused", "10k", "A12", "t24.tif", "+", "µm"), c("Focused",
>    "10k", "A12", "t36.tif", "+", "µm"), c("Focused", "10k",
>    "A12", "t48.tif", "+", "µm"), c("Focused", "10k", "B12",
>    "t04.tif", "+", "µm"), c("Focused", "10k", "B12", "t08.tif",
>    "+", "µm"))
>
> # Test the waters with one element
> cat(unlist(ls[1])[1:4])      # WHY DOES THE COMMAND PROMPT NOT APPEAR ON
> NEXT LINE AS USUAL???
>
> # Appears to work except for command prompt glitch
>
> # Attempts to use tapply() don't get me anywhere
> file <- tapply(unlist(ls), list(1:length(unlist(ls))),
> cat(unlist(ls[1])[1:4]))
>
> I'm grateful for an approach to putting my vector together, but I'd also
> love to understand the headache I've apparently given the command parser.
>  I'm apparently doing some "no no".
>
> Thanks,
>
> Rob
>
> > R.Version()
> $platform
> [1] "i386-pc-mingw32"
>
> $arch
> [1] "i386"
>
> $os
> [1] "mingw32"
>
> $system
> [1] "i386, mingw32"
>
> $status
> [1] ""
>
> $major
> [1] "2"
>
> $minor
> [1] "12.1"
>
> $year
> [1] "2010"
>
> $month
> [1] "12"
>
> $day
> [1] "16"
>
> $`svn rev`
> [1] "53855"
>
> $language
> [1] "R"
>
> $version.string
> [1] "R version 2.12.1 (2010-12-16)"
>
>
>        [[alternative HTML version deleted]]
>
>
> ______________________________________________
> 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.
>
>

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