--- Matrix#[]=(i,j,x)
    (i,j)Ǥxѹ롣

Υ᥽åɤϡmatrix.rbƤʤ
ʲˡȻ򼨤

    require 'matrix'

    class Matrix
      def []=(i,j,x)
        @rows[i][j]=x
      end
    end

    m=Matrix[[11,12],[21,22]]
    m[1,1]=-1
    p m #=> Matrix[[11,12],[21,-1]]

