Find the lowest location within rows where there are non-zero elements for each column in a matrix in MATLAB -

for example, have 4x6 matrix a:

a =       0     0     0     0     4     3      0     2     1     0     0     0      0     5     0     8     7     0      8     9    10     3     0     2 

i want find lowest location within rows of non-zero elements found each column. should go this:

column 1 => row 4 column 2 => row 2  column 3 => row 2 column 4 => row 3 column 5 => row 1 column 6 => row 1   

and result should following vector:

result = [4, 2, 2, 3, 1, 1]  

anyone has idea how obtain this?

this should it:

a = [0, 0, 0, 0, 4, 3;      0, 2, 1, 0, 0, 0;      0, 5, 0, 8, 7, 0;      8, 9, 10, 3, 0, 2];  indices = repmat((1:size(a))', [1, size(a, 2)]); indices(a == 0) = nan; min(indices, [], 1) 

here indices is:

indices =  1   1   1   1   1   1 2   2   2   2   2   2 3   3   3   3   3   3 4   4   4   4   4   4 

we set every element of indices nan wherever zero, gives us:

indices =   nan   nan   nan   nan     1     1 nan     2     2   nan   nan   nan nan     3   nan     3     3   nan   4     4     4     4   nan     4 

we take minimum of each column