[R] sum(table(v)) == length(v)

[R. Michael Weylandt]

On Sun, Sep 16, 2012 at 7:34 PM, Sam Steingold <sds at gnu.org> wrote:
> Is it possible to violate the identity sum(table(v)) == length(v) ??

Quite easily:

x <- c(1:5, NA)

sum(table(x)) # 5

length(x) # 6

Perhaps look at the exclude= argument.

Cheers,
Michael

> I see no way to do that and it holds in my small examples,
> but it is violated in the huge set I have:
>
> system.time(z <- unique(data.frame(u=U,s=S)))
> tab1 <- table(z$u)
> tab1 <- tab1[tab1>0] # S is factor so some counts were 0
> tab2 <- table(z$s)
> stopifnot(length(tab2) == nrow(z)) # yes
> stopifnot(sum(tab1) == nrow(z))  ### no!
> sum(tab1)
> 728587
> length(tab1)
> 503374
> length(tab2)
> 2112951
>
> --
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