Extract data from columm

    Dear all, 
    Could you help me? I have this matrix: 
    A= [1  3  0
    2  0  0
    3  0  0
    4  3  0
    5  0  0
    6  0  0
    7  0  0
    8  0  0
    9  0  0
    10  3  0
    11  0  0
    12  0  0
    13  5  0
    14  0  0
    15  0  0
    16  0  0
    17  6  0
    18  0  0
    19  0  0
    20  0  0
    21  3  0
    22  0  0
    23  0  0
    24  6  0
    25  0  0
    26  0  0
    27  0  0
    28  0  0
    29  0  0
    30  0  0
    31  0  0
    32  0  0.02256
    33  0  0.018682
    34  4  0.011892
    35  0  0.022345
    36  3  0.018794
    37  0  0.021655
    38  0  0.015674
    39  0  0.023075
    40  0  0.01055
    41  0  0.013921
    42  3  0.017497
    43  0  0.023766
    44  0  0.005467
    45  0  0.011991
    46  0  0.020437
    47  0  0.022869
    48  0  0.014035
    49  0  0.023253
    50  0  0.019731
    51  0  0.019275
    52  0  0.012172
    53  0  0.010395
    54  0  0.01569
    55  0  0.014506
    56  0  0.011423]
  I want to extract a submatrix which have number 0 in the columm 3. The result will be 
  B=[1  3  0
  2  0  0
  3  0  0
  4  3  0
  5  0  0
  6  0  0
  7  0  0
  8  0  0
  9  0  0
  10  3  0
  11  0  0
  12  0  0
  13  5  0
  14  0  0
  15  0  0
  16  0  0
  17  6  0
  18  0  0
  19  0  0
  20  0  0
  21  3  0
  22  0  0
  23  0  0
  24  6  0
  25  0  0
  26  0  0
  27  0  0
  28  0  0
  29  0  0
  30  0  0
  31  0  0]

and another submatrix which have all range with number 3 in the second columm. The results will be:

C= [1  3  0
4  3  0
10  3  0
21  3  0
36  3  0.018794
42  3  0.017497]. 
Thanks.

Answer 1

[KSSV]

A is your matrix:

%%Number 0 in col3 
B = A(A(:,3)==0,:) ;

%%Number 3 in col2 
C = A(A(:,2)==3,:) ;

[Quynh tran]

Thank you so much