CODEWITHSUNDEEP
r
Milad
Milad

Reputation: 339

Sum of cells with same row and column name in R

I have a matrix created using table() command in R in which rows and columns do not have same values. 

       0   1   2 
  1    1   2   3  
  2    4   5   6  
  3    7   7   8

How can I sum the elements with the same row and column name? In this example it is equal to (2+6=)8.

Upvotes: 4

Views: 1562

Answers (2)

flodel
flodel

Reputation: 89097

Another one, self-explanatory:

sum(x[colnames(x)[col(x)] == rownames(x)[row(x)]])

Upvotes: 1

Sven Hohenstein
Sven Hohenstein

Reputation: 81733

Here's one approach:

# find the values present in both row names and column names
is <- do.call(intersect, unname(dimnames(x)))

# calculate the sum
sum(x[cbind(is, is)])

where x is your table.

Upvotes: 3

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