[R] Finding NAs in DF

[Johannes Graumann]

Thank you very much got something running now based on this.

Joh

jim holtman wrote:

> building on the previous responses, does this give you what you want:
> 
>> x
>    A  B
> 1  1  1
> 2  2 NA
> 3 NA NA
> 4 NA  4
>> # determine where the NAs are
>> row.na <- apply(x, 1, is.na)
>> # now convert to list of columns with NAs
>> apply(row.na, 2, function(a) paste(colnames(x)[a], collapse = ','))
> [1] ""    "B"   "A,B" "A"
>>
>>
> 
> 
> On Mon, Jan 17, 2011 at 5:01 AM, Johannes Graumann
> <johannes_graumann at web.de> wrote:
>> Hi,
>>
>> What is an efficient way to take this DF
>>
>> data.frame(A=c(1,2,NA,NA),B=c(1,NA,NA,4))
>>
>> and get
>> c(NA,"TWO","BOTH","ONE")
>>
>> as the result, where NA corresponds to a row without "NA"s, TWO indicates
>> NA in the second and ONE in the first column.
>>
>> Thanks for any pointers.
>>
>> Joh
>>
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> 
> 
>