# Re: [R] maximum of identical elements in a vector

From: Gavin Simpson <gavin.simpson_at_ucl.ac.uk>
Date: Sun, 30 Mar 2008 21:55:32 +0100

On Sun, 2008-03-30 at 17:35 -0400, Daniel Malter wrote:
> Hi,
>
> the problem I have is seemingly very simple, but not simple enough for me to
> figure out. I just want to find the most (or least) frequent element in the
> vector.
>
> a=c("Alice","Alice","Alice","Alice","Bob","Bob")
> unique(a)
> length(which(a=="Alice"))

> a <- c("Alice","Alice","Alice","Alice","Bob","Bob")
> tab <- table(a)
> tab
a
Alice Bob

4 2
> which.max(tab)

Alice

1
> tab[which.max(tab)]

Alice

4

HTH G

>
>
> unique(a) shows me that the elements in my vector are "Alice" and "Bob". The
> latter expression gives 4 as the frequency of "Alice" in vector a.
> To find the maximum frequency of the unique elements, however, it assumes
> that I know that "Alice" is the most (or least) frequent element. Therefore,
> how can find that "Alice" is the most frequent element in this vector? I
> assume there is an easier way than computationally intensive loops (for long
> vectors).
>
> Cheers,
> Daniel
>
> -------------------------
> cuncta stricte discussurus
>
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> and provide commented, minimal, self-contained, reproducible code.

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