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.
Mike
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