[Rd] grep, gsub, sub have problems with NA values (PR#3078)

[Thomas Lumley]

On Thu, 22 May 2003 gregory_r_warnes at groton.pfizer.com wrote:

>
> In a string context, grep, gsub, sub are improperly treating NA (missing) as
> the string "NA", and returning unexpected results
>

as were chartr, abbreviate, substr, substring, strsplit. Fixed in r-devel,
for the case of NA in the `main' string. Haven't yet decided what to do
about
  grep(as.character(NA), x)
or
  substr(x,1,2)<-as.charcter(NA)



	-thomas