remove row from matrix

Question

Jakob Hannibal 2014-10-31

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/160803-remove-row-from-matrix

评论： Jakob Hannibal 2014-11-4

Hello!

I have a problem where I need to remove som rows from a matrix. I need to remove all numbers under 10 and over 60 from the first row and all negative numbers from the second row. The third row has to be between 1:4. I need to print if a row has been removed, so I know which rows are missing, which I haven't implemented in the code below. I have tried in many ways and has come up with this that removes the right rows, but I am sure it can be done in a smarter way…

clc;clear; false_data = [8 20 15 35 65 35; 0.1090 -0.50 0.5170 1.0860 0.9340 0.1090;1 2 3 4 6 1]'; approved_bacteria = [1 2 3 4];

for i = 1:length(false_data(:,1)) indices = 10 > false_data(:,1) | (false_data(:,1) > 60)

false_data(indices,:) = []; end

for i = length(false_data(:,2)) indices = false_data(:,2) < 0; false_data(indices,:) = []; end

for i = length(false_data(:,3)) indices = false_data(i,3) < 1 false_data(i,3) > 4; false_data(indices,:) = []; end false_data

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Answer 1

Sean de Wolski 2014-10-31

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https://ww2.mathworks.cn/matlabcentral/answers/160803-remove-row-from-matrix#answer_157232

在 MATLAB Online 中打开

This is how I'd do it.

% Bounds
lb = [10 0 1];
ub = [60 inf 4];
% Simulate data
n = 1000;
data = [randi(100,[n,1]) randn(n,1) rand(n,1)*10];
% Apply conditions
idxrmv = any(bsxfun(@lt,data,lb) | bsxfun(@gt,data,ub),2);
% Remove
data(idxrmv,:) = [];
% print
fprintf('Removed row %3.0i\n',find(idxrmv));

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Sean de Wolski 2014-10-31

loop over the rows of the matrix, find the columns in each row, print.

Jakob Hannibal 2014-11-4

在 MATLAB Online 中打开

When I run the function I get this errormessage:

Enter the filename to load: data0.txt

data =

0000    0.1090    1.0000
0000    0.0960    2.0000
0000         0    3.0000
0000    0.8000    5.0000
0000    1.0860    4.0000
0000    0.9340    2.0000
0000    0.1090    1.0000
0000    0.1000    1.0000
0000    0.1000    2.0000
0000    0.6000    3.0000
0000    0.8500    5.0000
0000    1.0800    4.0000
0000    0.9500    2.0000
0000    0.1100    1.0000