R:成对比较矩阵中的所有列 [英] R: Compare all the columns pairwise in matrix
问题描述
我有一个 41 行 6 列的矩阵.这就是第一部分的样子.
I have a matrix with 41 rows and 6 columns. This is how the first part looks like.
X13 X15 X17 X19 X21 X23
[1,] "7" "6" "5" "8" "1" "8"
[2,] "7" "6" "5" "8" "14" "3"
[3,] "7" "6" "1" "3" "12" "3"
[4,] "7" "6" "1" "5" "6" "14"
[5,] "2" "6" "1" "5" "16" "3"
[6,] "2" "3" "5" "5" "2" "3"
[7,] "7" "5" "5" "17" "7" "3"
[8,] "7" "2" "5" "2" "2" "14"
[9,] "2" "2" "10" "10" "2" "3"
[10,] "2" "2" "10" "5" "2" "6"
我的目标是,将所有列相互比较,看看有多少数字在两列中相等.我试着这样做:
My goal is, to compare all the columns with each other, and see, how many of the numbers are equal in the 2 columns. I tried to do it like this:
s <- sum(matrix[,1]==matrix[,2])
但是由于我需要比较所有可能的对,所以它无效.把它放在一个循环中会很好,但我不知道如何.
But since I need to compare all the possible pairs, it is not effective. It would be good to put this in a loop, but I have no idea how.
我想以 6x6 相似矩阵的形式得到我的结果.像这样:
And I would like to get my result in a form of a 6x6 similarity matrix. Something like this:
X13 X15 X17 X19 X21 X23
X13 0 0 3 2 2 3
X15 0 0 9 11 4 6
X17 3 9 0 5 1 3
X19 2 11 5 0 9 10
X21 2 4 1 9 0 9
X23 3 6 3 10 9 0
如您所见,当将一列与 iteslf 进行比较时,我想在矩阵中置零.
As you see, I would like to put zeros to the matrix when a column is compared to iteslf.
由于我是 R 初学者,这个任务对我来说真的很复杂.我需要将此比较用于 50 个矩阵,因此如果您能帮助我,我会很高兴.我将不胜感激任何提示/建议.我的英语也不是很好,但我希望我能很好地解释我的问题.:)
Since I am a beginner R user, this task semms really complicated to me. I need to use this comparison to 50 matrixes, so I would be glad if you could help me. I would appreciate any tips/suggestions. My english is not so good either, but I hope I could explain my problem well enough. :)
推荐答案
一种非矢量化(但可能更节省内存)的方法:
A non-vectorized, (but perhaps more memory-efficient) way of doing this:
# Fancy way.
similarity.matrix<-apply(matrix,2,function(x)colSums(x==matrix))
diag(similarity.matrix)<-0
# More understandable. But verbose.
similarity.matrix<-matrix(nrow=ncol(matrix),ncol=ncol(matrix))
for(col in 1:ncol(matrix)){
matches<-matrix[,col]==matrix
match.counts<-colSums(matches)
match.counts[col]<-0 # Set the same column comparison to zero.
similarity.matrix[,col]<-match.counts
}
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