filter matrix according to column

i have a matrix 10x60. It consists of entries with the number 0 or 1. I want to filter out all the rows, where the last five columns (55:60) have only 1 and no zero.

Answer 1

[Star Strider]

Try this:

M = randi([0 1], 10, 60);                       % Create Matrix
M(5, 55:60) = ones(1,6);                        % Row 5 Meets Criteria

row = all(M(:,55:60) == 1, 2);                  % Logical Vector, ‘1’ = Meets Criterion For Removal

Result = M(~row,:);

[AA]

thanks but i have several of those matrices in a cell array and i forgot to add that. your formula works but only for matrices not for matrices that are within a cell array.how can i apply your formula to matrices within a cell array? thanks.

[Star Strider]

Without having your cell array to work with, I cannot give an exact response. So, I’ll take a guess.

I would use the cellfun (link) function, possibly something like this:

M1 = randi([0 1], 10, 60);                      % Create Matrix
M2 = randi([0 1], 10, 60);                      % Create Matrix
M1(3, 55:60) = ones(1,6);                       % ‘M1’ Row 3 Meets Criteria
M2([5 7], 55:60) = ones(2,6);                   % ‘M2’ Rows 5,7 Meet Criteria
C = {M1, M2};                                   % Create Cell Array

Result = cellfun(@(M) M(~all(M(:,55:60) == 1, 2),:), C, 'Uni',0);

That works on my test matrices.

[AA]

thanks but the row number within the matrix is not displayed in your latest example.

[Jan]

@AA: Please include all details in the question already and do not provide more an more specifications later on. You did not ask for displaying anything before.

How do you want to display what?

[Star Strider]

@Jan — Thank you! My sentiments exactly!

@AA — These added assignments produce a logical cell array of the rows deleted, and using the find function, the row numbers of the deleted rows:

M1 = randi([0 1], 10, 60);                      % Create Matrix
M2 = randi([0 1], 10, 60);                      % Create Matrix
M1(3, 55:60) = ones(1,6);                       % ‘M1’ Row 3 Meets Criteria
M2([5 7], 55:60) = ones(2,6);                   % ‘M2’ Rows 5,7 Meet Criteria
C = {M1, M2};                                   % Create Cell Array

Result = cellfun(@(M) M(~all(M(:,55:60) == 1, 2),:), C, 'Uni',0);
RowsToDeleteLogical = cellfun(@(M) (all(M(:,55:60) == 1,2)), C, 'Uni',0);
RowsToDeleteNumeric = cellfun(@find, RowsToDeleteLogical, 'Uni',0);

Keep them as cell arrays, since there may be different numbers of rows deleted in each matrix. Address the individual cells in ‘RowsToDeleteNumeric’ to find the row numbers of the deleted cells in the corresponding matrices.

(Away for a few hours doing other things, since I have a life outside MATLAB Answers. It took about 10 minutes to write and test the additional assignment functions.)