finding values from matrix

Dear All

I have a matrix which is given by A= [20 140]. I want to find the location of elements in A which are greter than 45. Here is the matlab script which I tried to work upon but it gives me the whole value rather than location with respect to each coumn.

 for i = 1:20
Loc(ii,:)= find(A(i,:)>45);
 end

Thank you for your help

Answer 1

[Azzi Abdelmalek]

 out=A(A>45)

If you want the location:

idx=find(A>45)  % corresponding indices
out=A(idx)

[Ede gerlderlands]

This gives me the total values. What I want is the position(location) of values which are greater than 45. The locationhas to be with respect to the column ex. for column 1, 5, 65 ,78 etc... for column two 4, 5,8,12,...

[Azzi Abdelmalek]

Ok

A=randi(200,5)  % Example
[ii,jj]=find(A>45)

[Azzi Abdelmalek]

 A=[0 46 10 1; 47 5 48 5; 3 19 25 70]
out=arrayfun(@(x) max(find(A(x,:)>45)),1:size(A,1))

Answer 2

[Matt J]

 [i,j]=find(A>45);

[Ede gerlderlands]

I think am not clear with you. Is it not possible to get the location per co;umn? this gives me the over all location? isn't that? tnx

[Matt J]

Show us the desired output for this small example matrix

 A=[0 46 10 1; 47 5 48 5; 3 19 25 70]

And explain what form the output should take (cell, matrix, structure, etc...)

[Ede gerlderlands]

The answer will be 2 for the first column 1 and 3 foe the second as well as 4 for the third column. the output should be in str. Thank you

[Matt J]

The example matrix I gave you has 4 columns...

[Ede gerlderlands]

sorry, it has to be rows

[Matt J]

for k=1:size(A,1)

   S(k).locs = find(A(k,:)>45); 

end

[Edwin Herrera Vasco]

Thanks!!!

Answer 3

[Iain]

 A = [45 46; 42 43];
 logical_address = A>45;
 A(logical_address) %gives you a single 46. 
 linear_index =  find(logical_address);
 A(linear_index) % gives you a single 46. 
 [rowno, colno ] = sub2ind(size(A),linear_index);
 A(rowno,colno ) % gives you a single 46

Looking at your code, I think you're trying to do that row by row.

 find(A(i,:)>45) will give a vector containing the column number of each column which is >45 in that row of A - the length of this may vary from row to row, so you can't store the result in a simple vector - you'd need to use a cell array.