# [R] finding the most frequent row

Kjetil Brinchmann Halvorsen kjetil at acelerate.com
Fri Dec 10 23:18:29 CET 2004

```bogdan romocea wrote:

>Here's something that works. I'm sure there are better solutions (in
>particular the paste part - I couldn't figure out how to avoid typing
>a[i,1], ..., a[i,10]).
>
>a <- matrix(nrow=1000,ncol=10)
>for (i in 1:1000)
>	for (j in 1:10)
>		a[i,j] <- sample(1:0,1)
>
>b <- vector(mode="character")
>for (i in 1:1000)
>	b[i] <- paste(a[i,1],a[i,2],a[i,3],a[i,4],a[i,5],
>		a[i,6],a[i,7],a[i,8],a[i,9],a[i,10],sep="")
>
>
Or

b <- apply(a, 1, function(x) paste(x, sep="", collapse=""))

Kjetil

>#the most frequent row
>table(b)[table(b) == max(table(b))]
>
>HTH,
>b.
>
>
>-----Original Message-----
>From: Lisa Pappas [mailto:lisa.pappas at hci.utah.edu]
>Sent: Thursday, December 09, 2004 5:15 PM
>To: r-help at stat.math.ethz.ch
>Subject: [R] finding the most frequent row
>
>
>I am bootstrapping using a function that I have defined.  The
>"Statistic" of the function is an array of 10 numbers.  Therefore if
>I use 1000 replications,  the "t" matrix will have 1000 rows each of
>which is a bootstrap replicate of this 10 number array (10 columns).
>Is there any easy way in R to determine which row appears the most
>frequently?
>
>Thanks,
>Lisa Pappas
>
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--

Kjetil Halvorsen.

Peace is the most effective weapon of mass construction.
--  Mahdi Elmandjra

```