intersect_symmetric_matrix_character.R

symmetric_chr <- function(x) {
  res <- sapply(x, function(x1){
    sapply(x, function(x2) {i=length(intersect(na.omit(x1), na.omit(x2))); ifelse(is.na(i), 0, i)})
  })
  return(res)
}

#x <- data.frame(Samp1 = c(0,0,0,1,0,0,1,1,1), Samp2 = c(1,1,1,1,1,1,0,0,1))
x <- data.frame(Samp1 = c(letters[1:5],NA,NA), Samp2 = letters[1:7], sample3 = letters[10:16])
x

##   Samp1 Samp2 sample3
## 1     a     a       j
## 2     b     b       k
## 3     c     c       l
## 4     d     d       m
## 5     e     e       n
## 6  <NA>     f       o
## 7  <NA>     g       p

symmetric_chr(x)

##         Samp1 Samp2 sample3
## Samp1       5     5       0
## Samp2       5     7       0
## sample3     0     0       7