submatrix

Ways to use submatrix :

submatrix(Matrix,VisibleList) -- select columns
submatrix(MutableMatrix,VisibleList) -- see submatrix(Matrix,VisibleList) -- select columns
submatrix(Matrix,VisibleList,VisibleList) -- select part of a matrix
submatrix(MutableMatrix,VisibleList,VisibleList) -- see submatrix(Matrix,VisibleList,VisibleList) -- select part of a matrix

submatrix' -- exclude rows and/or columns of a matrix
submatrixByDegrees -- submatrix consisting of rows and columns in an interval or box of degrees
submatrix(Matrix,VisibleList) -- select columns
submatrix(Matrix,VisibleList,VisibleList) -- select part of a matrix
Matrix _ List -- select columns
Matrix ^ List -- select rows
Matrix _ Array -- component of map corresponding to summand of source
Matrix ^ Array -- component of map corresponding to summand of target