How do I read data from just first row of the cell

this is the 3x50 cell

[Geoff Hayes]

Bajdar - what does

 feature_vec(1,:)

return?

[madhan ravi]

@Geoff Hayes shouldn’t it be feature_vec{1,:} because it’s a cell ? Just curious.

[Image Analyst]

madhan, no. Just try it and see

for row = 1 : 3
  for col = 1 : 50
    ca{row, col} = rand(1, 4);
  end
end
row1 = ca(1,:) % Correct.
row1 = ca{1,:} % Incorrect.

The first way gives the entire row while the braces way gives only the first cell of the first row. See the FAQ on cell arrays.

[madhan ravi]

Thank you sir @ Image analyst

Answer 1

[Image Analyst]

Bajdar, just specify 1 for the first index of the cell array feature_vec.

array17 = feature_vec{1, 7} % Get array contained in row 1, column 7 of the cell array.

If you want all the arrays in all the cells of row 1, then you can do:

row1 = feature_vec(1,:) % row1 is another cell array - a row vector cell array.

Here row1 is a cell array that is a row vector of 50 cells. Each of those 50 cells contains a double array. To get any particular array in a specified column, use braces. For example to get the cell in the 8th column, do

cellContents18 = row1{8}; % Contents of the 8th cell will be a double array.

If you don't understand when to use braces (to refer to contents of the cell) and parentheses (to refer to the cells themselves), then see <https://matlab.wikia.com/wiki/FAQ#What_is_a_cell_array.3F the FAQ on cell arrays.) Don't worry - granted, it's a very tricky and confusing thing that is hard for a lot of people to grasp.

[Bajdar Nour]

Thanks, Image Analyst ..but it gives me an error row1 = feature_vec.mat(1,:) % row1 is another cell array - a row vector cell array.

Index exceeds matrix dimensions.

[Image Analyst]

Then do what I said instead of that! I did not say to add .mat after the feature_vec. This works fine, though I'm not sure what output you want.

% Make up random data in a 3-by-50 cell array
% where each cell contains a 4 number vector.
for row = 1 : 3
  for col = 1 : 50
    feature_vec{row, col} = rand(1, 4);
  end
end
endarray17 = feature_vec{1, 7} % Get array contained in row 1, column 7 of the cell array.
% If you want all the arrays in all the cells of row 1, then you can do:
row1 = feature_vec(1,:) % row1 is another cell array - a row vector cell array.
% Here row1 is a cell array that is a row vector of 50 cells.  Each of those 50 cells contains a double array.
% To get any particular array in a specified column, use braces.
% For example to get the cell in the 8th column, do
cellContents18 = row1{8}; % Contents of the 8th cell will be a double array.

[Image Analyst]

You're welcome. ?

Be sure to "Accept" the answer that helped the most. (You can only accept one).

[Bajdar Nour]

I have 3 different types of images each type contains 50 images..all images have been saved in 3X50 cell array..I want to separate each of them independently and save each one as .dat file (like row1.dat , row2.dat ,row3.dat) { Hint1: each image is double array and 9 features have been calculated. Hint2:feature_vec is .mat file}

[Image Analyst]

I don't see any reason to save/store all the images. Why are you doing that? Just process them in the loop and be done with that image.

See the FAQ: https://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

Answer 2

[Yuvaraj Venkataswamy]

if true
 feature_vec{1,:}
end

[Bajdar Nour]

Thanks, Yuvaraj V

[Yuvaraj Venkataswamy]

You are welcome

Answer 3

[Adusumilli Bala Surendra]

The following can help you. Try this.

z =

1×3 cell array

{3×3 double} {3×3 double} {3×3 double}

>> z{1}

ans =

0.00315 + 0.011925i 0.0008042 + 0.0071843i 0.0008042 + 0.0061306i

0.0008042 + 0.0071843i 0.00315 + 0.011925i 0.0008042 + 0.0065829i

0.0008042 + 0.0061306i 0.0008042 + 0.0065829i 0.00315 + 0.011925i

>> z{1}(1,:)

ans =

0.00315 + 0.011925i 0.0008042 + 0.0071843i 0.0008042 + 0.0061306i