UNIX-like "cut" command in R

On Mon, May 2, 2011 at 10:32 PM, Mike Miller <mbmiller+l at gmail.com> wrote:

On Tue, 3 May 2011, Andrew Robinson wrote:

try substr()

OK. ?Apparently, it allows things like this...

substr("abcdef",2,4)

[1] "bcd"

...which is like this:

echo "abcdef" | cut -c2-4

But that doesn't use a delimiter, it only does character-based cutting, and
it is very limited. ?With "cut -c" I can do stuff this:

echo "abcdefghijklmnopqrstuvwxyz" | cut -c-3,12-15,17-

abclmnoqrstuvwxyz

It extracts characters 1 to 3, 12 to 15 and 17 to the end.

That was a great tip, though, because it led me to strsplit, which can do
what I want, however somewhat awkwardly:

y <- "a b c d e f g h i j k l m n o p q r s t u v w x y z"
paste(unlist(strsplit(y, delim))[c(1:3,12:15,17:26)], collapse=delim)

[1] "a b c l m n o q r s t u v w x y z"

That gives me what I want, but it is still a little awkward. ?I guess I
don't quite get what I'm doing with lists. ?I'm not clear on how this would
work with a vector of strings.

Try this:

read.fwf(textConnection("abcdefghijklmnopqrstuvwxyz"), widths = c(3, 8, 4, 1, 10), colClasses = c(NA, "NULL"))

  V1   V3         V5
1 abc lmno qrstuvwxyz