[R] Mode in case of discrete or categorial data

[Prof Brian Ripley]

On Fri, 12 Nov 2004, Liaw, Andy wrote:

> You might want to do a bit to handle NAs, as table() excludes them by
> default.  Also, you could write it a bit cleaner as:
>
> Mode <- function(x) {
>    tab <- table(x)
>    m <- names(tab)[tab == max(tab)]
>    if (is.numeric(x)) m <- as.numeric(m)
>    m
> }
>
> (Generally I try avoiding constructs like:
>   if (cond) var <- alt1 else var <- alt2
> especially when alt1 and alt2 are very similar.  If you need to make changes
> later, it's easy to change one and forget the other, etc.  I believe Martin
> also made this point in his talk at useR! 2004.)

Also,

    var <- if(cond) alt1 else alt2

is more idiomatic S (and easier to read).

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595