[R] Returning a factor from vapply

[Jeff Newmiller]

Such manipulations are usually better performed in character data.  Convert to factor only after the vector is complete. 
-- 
Sent from my phone. Please excuse my brevity.

On November 25, 2015 3:49:24 AM PST, Axel Urbiz <axel.urbiz at gmail.com> wrote:
>Hello, 
>
>I would like to return a factor from vapply, which looks it cannot be
>done directly since a factor is typeof() numeric. So I’m not sure if
>the solution below is the standard approach to handle this. My concern
>is that the factor levels are mixed up in the results (as shown in the
>last line of code), which is undesirable. 
>
>set.seed(1)
>df <- data.frame(x1 = runif(100), x2 = runif(100))
>
>
>mycuts <- function(x) {
>  
>xc <- cut(x, breaks = unique(quantile(x, seq(0, 1, 1/4), na.rm =
>TRUE)),
>            include.lowest = TRUE)
>  as.character(xc)
>  
>}
>
>head(df_out <- data.frame(vapply(df, mycuts, character(nrow(df)))))
>
>identical(levels(df_out$x1), levels(cut(df$x1, breaks =
>unique(quantile(df$x1, 
>                                        seq(0, 1, 1/4), na.rm = TRUE)),
>                                        include.lowest = TRUE)))
>
>
>Thanks for any pointers. 
>
>Axel.
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