text matching and substitution

I am trying to simplify a text variable by matching and replacing it with a
string in another vector

so for example in
colours <- paste(letters,colours(),"stuff",LETTERS)

find and replace with ("red","blue","green","gray","yellow","other")  -
irrespective of case

its a large dataset, so i'd like to be able to do this as efficiently as
possible.

thanks for any help

	[[alternative HTML version deleted]]

thanks stephan.  i'd been trying to make gsub work, but couldnt make it
replace the whole expression.  so i'd resorted to trying to loop with grep -
but with two problems.   firstly, i cant seem to make the loop 'remember'
the substitutions it makes (see below).  secondly, it feels like this is a
really inefficient way of doing something quite simple anyhow.

colours <- as.character(paste(letters,colours(),"stuff",LETTERS))
target <- c("red","blue","green","gray")
new.colour <-colours
for (i in length(target)) {
    x <- target[i]
    new.colour[grep((x),new.colour)] <- x
    return(new.colour)
    }




On Sat, Mar 28, 2009 at 9:45 AM, Stephan Kolassa <Stephan.Kolassa at gmx.de>wrote:

Hi Simeon,

?gsub

HTH,
Stephan

simeon duckworth schrieb:

I am trying to simplify a text variable by matching and replacing it with
a
string in another vector

so for example in
colours <- paste(letters,colours(),"stuff",LETTERS)

find and replace with ("red","blue","green","gray","yellow","other")  -
irrespective of case

its a large dataset, so i'd like to be able to do this as efficiently as
possible.

thanks for any help

       [[alternative HTML version deleted]]