MATLAB: How can delete matrix randomly

matrix

       y =[1   2   0.075  0.100  0.000  1.000 
           2   3   0.080  0.110  0.000  1.000
           2   4   0.090  0.180  0.000  1.000
           3   9   0.040  0.040  0.000  1.000 
           4   5   0.040  0.040  0.000  1.000
           1   6   0.110  0.110  0.000  1.000
           5   14  0.090  0.120  0.000  1.000
           6   7   0.080  0.110  0.000  1.000
           6   8   0.110  0.110  0.000  1.000
           7   9   0.110  0.110  0.000  1.000
           7   10  0.080  0.110  0.000  1.000
           8   12  0.040  0.040  0.000  1.000 
           1   11  0.110  0.110  0.000  1.000
           11  12  0.090  0.120  0.000  1.000
           11  13  0.080  0.110  0.000  1.000
           13  14  0.040  0.040  0.000  1.000];

I have matrix y and I want to delete 3 rows randomly. To be like this.

How can I do?

       y =[1   2   0.075  0.100  0.000  1.000 
           2   3   0.080  0.110  0.000  1.000
           2   4   0.090  0.180  0.000  1.000
           4   5   0.040  0.040  0.000  1.000
           1   6   0.110  0.110  0.000  1.000
           6   7   0.080  0.110  0.000  1.000
           6   8   0.110  0.110  0.000  1.000
           7   9   0.110  0.110  0.000  1.000
           7   10  0.080  0.110  0.000  1.000
           1   11  0.110  0.110  0.000  1.000
           11  12  0.090  0.120  0.000  1.000
           11  13  0.080  0.110  0.000  1.000
           13  14  0.040  0.040  0.000  1.000];

Best Answer

Let y be your matrix:

[nx,ny] = size(y) ; 
idx = randsample(1:nx,3) ; 
y(idx,:) = []

Note that, yopu are deleting rows..not columns.

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MATLAB: Compare values in two matrix with different length by time in first row

Hi,

You can perform the task mentioned above as follows: -

clc; clear;
%% Input variables
Matrix_R = [0.020 77; 0.030 98; 0.040 79; 0.070 95; 0.080 96; ...
    0.090 99; 0.100 100; 0.100 200; 0.120 44];
Matrix_G = [0.010 75; 0.020 75; 0.030 75; 0.040 77; 0.050 78; 0.060 96; ...
    0.070 99; 0.080 100; 0.090 100; 0.100 110; 0.110 100; 0.120 100; 0.130 110];
tol = 10;
%% Initialize output matrix, where
% column 1 -- all the elements in the Matrix_G with appropriate repetition
% colum 2 -- output column, where -1 -> false negative; 1 -> true positive; 0 -> False negative and False positive
freq = [Matrix_G(:,1), histc(Matrix_R(:,1),Matrix_G(:,1))]; % get frequncy of each element of Matrix_G in Matrix_R
repetitionNumber = freq(freq(:,2) > 1, 1);  % get the element which repeats more than once
repetitionTimes = freq(freq(:,2) > 1, 2);   % get number of time element repeats more than once
outputTime = sort([freq(:,1); repelem(repetitionNumber, repetitionTimes - 1)]); % sort w.r.t time
output = [outputTime -1*ones(size(outputTime,1), 1)];   % initialize output matrix with all time rows == -1
%% 
% get common elements between Matrix_R and Matrix_G
[Lia,Locb] = ismember(Matrix_R(:,1), Matrix_G(:,1));
A = Matrix_R(Lia, 2);
B = Matrix_G(Locb, 2);
toleranceCheck = abs(A-B) <= 10;   % find elements which are within the tolerance
output(ismember(output(:,1), Matrix_R(:,1)), 2) = toleranceCheck;

Best Answer

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MATLAB: Get in Order respond when using “eig” command

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