How to call out rows that contains a value X in column Z of matrix A?

If I have a matrix A what command would return the number of each row in A that contains the value X in column Z?

EXAMPLE:

 A:
   20.0000    1.0000    8.3333
    2.0000    2.0000   32.6667
   45.0000    1.0000    5.3333
    4.0000    1.0000    8.3333
   54.0000    3.0000   25.0000
   38.0000    3.0000   33.3333
    7.0000    2.0000   16.6667
    8.0000    1.0000   10.3333

 somefunction(3,A(:,2)) = [5,6]

5 and 6 being the rows in A that contain the value 3 in column 2

Thank you!

Answer 1

[the cyclist]

find(A(:,Z)==X)

in general, and

find(A(:,2)==3)

for the specific case you mention.

[sono]

Unfortunately that doesn't seem to work:

 >> find(A(:,2)==3)

 ans =

     []

[the cyclist]

Are you sure that your values in the second column are _exactly _equal to 2? Or might they be slightly off, due to floating point precision?

I think you fill find the following code does what you expect:

A = [20.0000    1.0000    8.3333
      2.0000    2.0000   32.6667
     45.0000    1.0000    5.3333
      4.0000    1.0000    8.3333
     54.0000    3.0000   25.0000
     38.0000    3.0000   33.3333
      7.0000    2.0000   16.6667
      8.0000    1.0000   10.3333]

find(A(:,2)==3)

Answer 2

[Azzi Abdelmalek]

If you have a cell array

A={'Value'    'Count'   'Percent'
    1        1     '10.00%'
    2        3     '30.00%'
    3        1     '10.00%'
    4        1     '10.00%'
    5        0      '0.00%'
    6        0      '0.00%'
    7        3     '30.00%'
    8        0      '0.00%'
    9        1     '10.00%'}
out=find(cell2mat((A(2:end,2)))==3)

[sono]

Thanks.

I think working with a non cell array is simpler for me right now but I'll keep it in mind for future use.