title: R modify an element matrix in csv file
body: <p>I think my question is not very complicated but i don't find solution.
  I want to modify just a element of a matrix in a csv format. 
  I use the write.table command for write the matrix but i don't know how change the element A[i,j] and not rewrite all the matrix. For example if i use the code below all the matrix is rewrite and not just the element A[2,2].</p>
  
  <pre><code> A&lt;- rbind(c(1,2,3),c(4,5,6),c(7,8,9))
   A
   [,1] [,2] [,3]
   [1,]    1    2    3
   [2,]    4    5    6
   [3,]    7    8    9
   write.table(A, file = "A.csv", sep = "\t", col.names =T, row.names =T)
   #I modify 2 elements of matrix
   A[2,2]&lt;-0
   A[1,1]&lt;-0
   A
        [,1] [,2] [,3]
   [1,]    0    2    3
   [2,]    4    0    6
   [3,]    7    8    9
   write.table(A[2,2], file = "A.csv", sep = "\t", col.names =T,
  </code></pre>
  
  <p>Of course the code below print just the element A[2,2]</p>
  
  <pre><code> write.table(A[2,2], file = "A.csv", sep = "\t", col.names =T,     row.names=T)
  </code></pre>
  
  <p>But i would like just modify the element A[2,2] in the csv file
  Thanks for help</p>