Try this:
DF <- data.frame(start=1:5,end=10:6)
# apply(DF,1,function(row){ return(row$start + row$end) })
DF$start + DF$end
apply(DF, 1, function(row) row[["start"]] + row[["end"]])
apply(DF, 1, function(row) row["start"] + row["end"])
On 8/9/07, Ido M. Tamir <tamir at imp.univie.ac.at>
wrote:> Dear All,
>
> I would like to know why $ was deprecated for atomic vectors and
> what I can use instead.
>
> I got used to the following idiom for working with
> data frames:
>
> df <- data.frame(start=1:5,end=10:6)
> apply(df,1,function(row){ return(row$start + row$end) })
>
> I have a data.frame with named columns and
> use each row to do something. I would like the
> named index ($) because the column position
> in the data frame changes from time to time.
> The data frame is read from files.
>
> thank you very much,
>
> ido
>
>
>
>
> '$' returns 'NULL' (with a warning) except for recursive
> objects, and is only discussed in the section below on recursive
> objects. Its use on non-recursive objects was deprecated in R
> 2.5.0.
>
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>