[R] count frequency

[(Ted Harding)]

On 17-Sep-10 12:19:10, Alaios wrote:
> Hello everyone,
> please consider the following lines of a matrix
> 
> [574,]   59   32
> [575,]   59   32
> [576,]   59   32
> [577,]   59   32
> [578,]   59   32
> [579,]   59   32
> [580,]   59   32
> [581,]   60   32
> [582,]   60   33
> [583,]   60   33
> [584,]   60   33
> [585,]   60   33
> [586,]   60   33
> [587,]   60   33
> [588,]   60   33
> [589,]   60   33
> [590,]   60   33
> [591,]   61   33
> [592,]   61   33
> [593,]   61   33
> [594,]   61   33
> [595,]   61   33
> [596,]   61   33
> [597,]   61   33
> [598,]   61   33
> [599,]   61   33
> [600,]   61   33
> [601,]   62   34
> 
> Is it possible somehow to count the similarities between the first and
> second 
> column and put them on a third column like this?
> 
> 59 32 3
> 60 33 5
> 62 34 1
> 
> where (3,5,1 are the frequencies for (59,32), (60,33) and (62,34)
> 
> Best Regards
> Alex

Does the following do what you want?

  a <- c(59,59,59,59,59,59,59,60,60,60,60,60,60,60,
         60,60,60,61,61,61,61,61,61,61,61,61,61,62)
  b <- c(32,32,32,32,32,32,32,32,33,33,33,33,33,33,
         33,33,33,33,33,33,33,33,33,33,33,33,33,34)

  table(data.frame(a=a,b=b))
  #     b
  # a    32 33 34
  #   59  7  0  0
  #   60  1  9  0
  #   61  0 10  0
  #   62  0  0  1

  T <- t(as.matrix(table(data.frame(a=a,b=b))))
  L <- c(table(data.frame(a=a,b=b)))
  B <- as.integer(rep(rownames(T),each=ncol(T)))
  A <- as.integer(rep(colnames(T),nrow(T)))
  cbind(A,B,L)[L>0,]
  #       A  B  L
  # [1,] 59 32  7
  # [2,] 60 32  1
  # [3,] 60 33  9
  # [4,] 61 33 10
  # [5,] 62 34  1

Ted.

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E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
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Date: 17-Sep-10                                       Time: 14:15:03
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