M=round(10*rand(9))

M =

    10     4     4     6     8     5     2     6     8
     2     6     9     3     5     7     7     8     6
     6     8     1     2     2     4     4     7     4
     5     9     4     0     7     3     9     3     7
     9     7     8     7     8     2     9     3     5
     8     2     0     4     0     2     6     3     4
     5     4     1     9     7     7     5     5     7
     0     9     2     5     4     3     9     7     6
     8     9     2     4     8     5     8     3     8

M(1:3,1:3) = zeros(3)

M =

     0     0     0     6     8     5     2     6     8
     0     0     0     3     5     7     7     8     6
     0     0     0     2     2     4     4     7     4
     5     9     4     0     7     3     9     3     7
     9     7     8     7     8     2     9     3     5
     8     2     0     4     0     2     6     3     4
     5     4     1     9     7     7     5     5     7
     0     9     2     5     4     3     9     7     6
     8     9     2     4     8     5     8     3     8

M(4:6,4:6)=1

M =

     0     0     0     6     8     5     2     6     8
     0     0     0     3     5     7     7     8     6
     0     0     0     2     2     4     4     7     4
     5     9     4     1     1     1     9     3     7
     9     7     8     1     1     1     9     3     5
     8     2     0     1     1     1     6     3     4
     5     4     1     9     7     7     5     5     7
     0     9     2     5     4     3     9     7     6
     8     9     2     4     8     5     8     3     8

M(end-2:end,end-2:end)=9

M =

     0     0     0     6     8     5     2     6     8
     0     0     0     3     5     7     7     8     6
     0     0     0     2     2     4     4     7     4
     5     9     4     1     1     1     9     3     7
     9     7     8     1     1     1     9     3     5
     8     2     0     1     1     1     6     3     4
     5     4     1     9     7     7     9     9     9
     0     9     2     5     4     3     9     9     9
     8     9     2     4     8     5     9     9     9

N=round(10*rand(7))

N =

    10     9     7     5     6     8     0
     5     7     3     3     2     1     8
     9     1     5     4     4     6    10
     2     0     1     2     8     1    10
    10     9    10     6     7     4     8
     3     2     6     8     5     3     4
     3     3     4     5     6     9     5

N(1,1:end)

ans =

    10     9     7     5     6     8     0

N(1,:)

ans =

    10     9     7     5     6     8     0

N(:,:)

ans =

    10     9     7     5     6     8     0
     5     7     3     3     2     1     8
     9     1     5     4     4     6    10
     2     0     1     2     8     1    10
    10     9    10     6     7     4     8
     3     2     6     8     5     3     4
     3     3     4     5     6     9     5


N(1:3,:)

ans =

    10     9     7     5     6     8     0
     5     7     3     3     2     1     8
     9     1     5     4     4     6    10

N(:,1:5)

ans =

    10     9     7     5     6
     5     7     3     3     2
     9     1     5     4     4
     2     0     1     2     8
    10     9    10     6     7
     3     2     6     8     5
     3     3     4     5     6

N(1:2,:)=1

N =

     1     1     1     1     1     1     1
     1     1     1     1     1     1     1
     9     1     5     4     4     6    10
     2     0     1     2     8     1    10
    10     9    10     6     7     4     8
     3     2     6     8     5     3     4
     3     3     4     5     6     9     5

N(:,5:end)=5

N =

     1     1     1     1     5     5     5
     1     1     1     1     5     5     5
     9     1     5     4     5     5     5
     2     0     1     2     5     5     5
    10     9    10     6     5     5     5
     3     2     6     8     5     5     5
     3     3     4     5     5     5     5

L=round(7*rand(4,6))

L =

     1     5     3     6     4     3
     5     3     7     4     4     0
     2     5     5     1     3     0
     7     2     1     1     4     2

L = L(:,end:-1:1)

L =

     3     4     6     3     5     1
     0     4     4     7     3     5
     0     3     1     5     5     2
     2     4     1     1     2     7

a=rand(1,6)

a =

  Columns 1 through 5 

    0.0129    0.3840    0.6831    0.0928    0.0353

  Column 6 

    0.6124

a=rand(1,6)

a =

    0.6085    0.0158    0.0164    0.1901    0.5869    0.0576

a([1 end])=a([end 1])

a =

    0.0576    0.0158    0.0164    0.1901    0.5869    0.6085

P=round(10*rand(6))

P =

     4     4     5     3     2     8
     6     4     6     3     2     2
     7     2     1     9     0     2
     7     7     5     2     1    10
     1     7     7     8     6     4
     5     7     9     9     2     3

P([1 end],[1,end])=P([end 1],[end 1])

P =

     3     4     5     3     2     5
     6     4     6     3     2     2
     7     2     1     9     0     2
     7     7     5     2     1    10
     1     7     7     8     6     4
     8     7     9     9     2     4

P=round(10*rand(6))

P =

     3     5     2     1     3     5
     4     9     6     8     2     8
     4     9    10     4     2     5
     6     3     7     9     2     5
     1     2     9     7     4     5
     0     9     0     7     9     4

P=round(10*rand(6))

P =

     9    10     4     8     6     7
     0     6     0     4     6     4
     3     4     4     6     2     6
     0     2     8     7     5     7
     7     6     8     2     9     4
     7     7     9     9     3     4

P([1 end],[1 end])=5

P =

     5    10     4     8     6     5
     0     6     0     4     6     4
     3     4     4     6     2     6
     0     2     8     7     5     7
     7     6     8     2     9     4
     5     7     9     9     3     5

diary off