regular exprs
On Nov 7, 2010, at 10:15 AM, Dimitris Rizopoulos wrote:
Dear All,
I would appreciate any help with the following: given the vector 'x'
x <- c("Ass1", "Ass.s1", "Ass2", "Ass.s2")
I would like to pick up the positions where the character string
contains "Ass" but does not contain "Ass.s", so for 'x' that would
be positions 1 and 3.
> x[ grepl("Ass", x) & !grepl("Ass\\.s", x) ]
[1] "Ass1" "Ass2"
HTH;
David > > I guess this could be programmed around grep() using a suitable > regular expression, but I haven't managed to succeed. > > Thanks in advance. > > Best, > Dimitris > > -- > Dimitris Rizopoulos > Assistant Professor David Winsemius, MD West Hartford, CT