On 22 Aug 2007, at 20:16, Duncan Murdoch wrote:
> On 8/22/2007 11:50 AM, Martin Maechler wrote:
>> Consider this example code
>>
>> c1 <- letters[1:7]; c2 <- LETTERS[1:7]
>> c1[2] <- c2[3:4] <- NA
>> rbind(c1,c2)
>>
>> ## [,1] [,2] [,3] [,4] [,5] [,6] [,7]
>> ## c1 "a" NA "c" "d" "e" "f" "g"
>> ## c2 "A" "B" NA NA "E" "F" "G"
>>
>> paste(c1,c2)
>>
>> ## -> [1] "a A" "NA B" "c NA" "d NA" "e E" "f F" "g G"
>>
>> where a more logical result would have entries 2:4 equal to
>> NA
>> i.e., as.character(NA)
>> aka NA_character_
>>
>> Is this worth persuing, or does anyone see why not?
>
> A fairly common use of paste is to put together reports for human
> consumption. Currently we have
>
>> p <- as.character(NA)
>> paste("the value of p is", p)
> [1] "the value of p is NA"
>
> which looks reasonable. Would this become
>
>> p <- as.character(NA)
>> paste("the value of p is", p)
> [1] NA
>
> under your proposal? (In a quick search I was unable to find a real
> example where this would happen, but it would worry me...)
At least stop() seems to include such a case:
message <- paste(args, collapse = "")
and we may expect there are NAs sometimes in stop().
cheers, jazza
--
Jari Oksanen, Oulu, Finland
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