[R] in which column is an entry?

[Chuck Cleland]

Christian Schulz wrote:
> df  is a data.frame with 43 colums and 29877 rows with lot of NA.
> I want the column number for all respondendts in one column 
> where is the first entry >=0 as columnnumber.
> 
> my first step:
>  time <- function(df)
> +     {        for (i in 1:length(df [,1])) {    
> +     which(df[i,1]:df[i,43] >= 0)
> +     }
> +            }
> 
> 
>>t1 <-  time(YS)
> 
> Error in df[i, 1]:df[i, 43] : NA/NaN argument

   I am not sure, but I think you might want something like this:

t1 <- apply(df, 1, function(x){
             ifelse(all(is.na(x)) | all(na.omit(x) < 0),
             NA, which(x >= 0))})

hope this helps,

Chuck Cleland

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