how to take every row in matrix?

i have matrix 1000x1000. i want collect data at row 2 until 4 , 6 until 8 , 8 until 10 until end

Answer 1

[Stephen23]

You could use MAT2CELL, just generate the sizes based on your matrix dimensions and requirements:

A = randi(10,10,10)

A = 10×10

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

C = mat2cell(A(2:end,:),[3,3,3],10)

C = 3×1 cell array
    {3×10 double}
    {3×10 double}
    {3×10 double}

C{1},C{2},C{3}

ans = 3×10

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

ans = 3×10

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

ans = 3×10

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

Answer 2

[KSSV]

iwant = A(2:2:end,:) ; 

[daniel danish]

no. it din't answer my question.

for example i have matrix A=randi(10,10,10)

A =

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

i want every 2 row until 4 row until end, which mean like this

 B=
     5     4     4     3     7     4     8     5     8     6
    10     4     5     5     7     7    10     6     5     8
     7     4     5     5     1     5     8     4     8     1
  C=
     8    10     9     5     6     7     9     9     3     1
     2     7     3     9     7     3     9     3     2     7
     3     3     9     9     2     5     1     3     5     5

and i want to calculate the mean all of that