On 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"))
Perhaps:
> sapply(ls1, paste, collapse="")
[1] "Focused10kA12t04.tif+µm" "Focused10kA12t08.tif+µm"
[3] "Focused10kA12t12.tif+µm" "Focused10kA12t16.tif+µm"
[5] "Focused10kA12t20.tif+µm" "Focused10kA12t24.tif+µm"
[7] "Focused10kA12t36.tif+µm" "Focused10kA12t48.tif+µm"
[9] "Focused10kB12t04.tif+µm" "Focused10kB12t08.tif+µm"
(I changed the name and will not illustrate its assignment to "file".
It is generally considered poor programming practice to use function
names for variable objects.)
--
David.
# 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)"
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David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
