regex -> negate a word
On Mon, 19 Jan 2009, Rolf Turner wrote:
On 19/01/2009, at 10:44 AM, Gabor Grothendieck wrote:
Well, that's why it was only provided when you insisted. This is not what regexp's are good at. On Sun, Jan 18, 2009 at 4:35 PM, Rau, Roland <Rau at demogr.mpg.de> wrote:
Thanks! (I have to admit, though, that I expected something simple)
It may not be what regexp's are good at, but the grep command in unix/linux does what is required *very* simply via the ``-v'' flag. I conjecture that it would not be difficult to add an argument with similar impact to the grep() function in R.
Indeed. I have often wondered why grep() returned indices, when a logical vector would seem more natural in R (and !grep(...) would have been all that was needed). Looking at the code I see it does in fact compute a logical vector, just not return it. So adding 'invert' (the long-form of -v is --invert) is a job of a very few lines and I have done so for 2.9.0.
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595