R help - Apr 2013 - converting blank cells to NAs

You can use na.strings="" in read.table() or read.csv()


library(stringr)

vec1<-unlist(str_split(readLines(textConnection("3,7,11,,12,14,15,,17,18,19")),","))
?vec1[vec1==""]<- NA
?vec1
# [1] "3"? "7"? "11" NA?? "12"
"14" "15" NA?? "17" "18" "19"

#or
scan(text="3,7,11,,12,14,15,,17,18,19",sep=",")
#Read 11 items
?#[1]? 3? 7 11 NA 12 14 15 NA 17 18 19
set.seed(25)
?arr1<- array(sample(letters,40,replace=TRUE),dim=c(5,4,2))
arr1[5,3,2]<-""
arr1[arr1==""]<- NA
arr1[,,2]
#???? [,1] [,2] [,3] [,4]
#[1,] "b"? "h"? "v"? "k" 
#[2,] "l"? "b"? "j"? "y" 
#[3,] "c"? "p"? "g"? "j" 
#[4,] "e"? "n"? "c"? "e" 
#[5,] "h"? "g"? NA?? "d"?

?arr2<- array(1:40,dim=c(5,4,2))
?arr2[5,3,2]<- ""
arr2[arr2==""]<- NA
arr2<- apply(arr2,c(2,3),as.numeric)
arr2[,,2]
#???? [,1] [,2] [,3] [,4]
#[1,]?? 21?? 26?? 31?? 36
#[2,]?? 22?? 27?? 32?? 37
#[3,]?? 23?? 28?? 33?? 38
#[4,]?? 24?? 29?? 34?? 39
#[5,]?? 25?? 30?? NA?? 40


A.K.


>Is there a way to convert blank cells in a vector or array into
"NA"s?
?Alternatively, is there a test for blank cells the way one can use 
is.na to test for >NAs? 
>
>Thanks in advance.

Hi,
I am not sure about the problem.
If your non-numeric vector is like:
a,b,,d,e,,f

vec1<-unlist(str_split(readLines(textConnection("a,b,,d,e,,f")),","))
?vec1[vec1==""]<- NA
?vec1
#[1] "a" "b" NA? "d" "e" NA?
"f"

If this doesn't work, please provide an example vector.
A.K.


>Thanks for the response. ?That seems to do the trick as far replacing the
empty
cells with <NA>, however, the problem remains that the vector is 
not >numeric. ?This was the reason I wanted to replace the empty cells 
with NAs in the first place. ?Forcing the vector with as.numeric 
afterwards doesn't >seem to work either, I get nonsensical results.