This is documentation for Mathematica 5, which was
based on an earlier version of the Wolfram Language.

 3.7.2 Getting and Setting Pieces of Matrices Ways to get pieces of matrices. Matrices in Mathematica are represented as lists of lists. You can use all the standard Mathematica list-manipulation operations on matrices. Here is a sample matrix. In[1]:= t = Array[a, {3, 3}] Out[1]= This picks out the second row of the matrix. In[2]:= t[[2]] Out[2]= Here is the second column of the matrix. In[3]:= t[[All, 2]] Out[3]= This picks out a submatrix. In[4]:= Take[t, {1, 2}, {2, 3}] Out[4]= Resetting parts of matrices. Here is a matrix. In[5]:= m = {{a, b}, {c, d}} Out[5]= This resets the 2, 2 element to be x, then shows the whole matrix. In[6]:= m[[2, 2]] = x; m Out[6]= This resets all elements in the second column to be z. In[7]:= m[[All, 2]] = z; m Out[7]= This separately resets the two elements in the second column. In[8]:= m[[All, 2]] = {i, j}; m Out[8]= This increments all the values in the second column. In[9]:= m[[All, 2]]++; m Out[9]=