Delete rows from matrix

2014 3 4
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更新时间：2014 3 4
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Hallo,I need help!
I have 110 matrix 64 line x 2200 column and I would like to delete some columns from each matrix, so I am obliged to use loops for each matrix. I am looking for a predefined function to delete the columns. This is a small algorithm explaining what I mean:
for i=1:110
delete( matrix(:,j:j+5)) from matrix;
end

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Image Analyst
Image Analyst 2014-3-4
编辑：Image Analyst 2014-3-4
WHY are you obligated to use loops rather than the vectorized method the others suggested? Do you just think you do (because you don't know how to use MATLAB's vectorization capability), or did your professor/instructor mandate it?
Amal
Amal 2014-3-4
I have other instruction in the same loop and I need each iteration a matrix, each matrix contains the same columns, but in different order. I think my problem is solved finally :) I am waiting for matlab execution to verify my matrix. I used this instruction: matrix(:,j:j+5)=[];
thank you for your help :)

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0 个投票

IN the title you mention rows. In the question you mention columns. example:
A1=randi(10,64, 2200);
A2=randi(10,64, 2200);
A3=randi(10,64, 2200);
...
An=randi(10,64, 2200);
mat=[A1;A2;A3;...An];
startcolumn=11;
step=11;
mat(:,[startcolumn:step:end])=[]

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Amal
Amal 2014-3-4
thank you so much, I used the last instruction from the beginning, but it didn't work, but after restarting MATLAB it worked ;)

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Iain
Iain 2014-3-4

0 个投票

To "delete"
matrix = eye(5);%5x5 identity matrix
list_o_cols_to_delete = [1 3 5];
matrix(:,list_o_cols_to_delete) = []
To only use the bits you want:
matrix = eye(5);%5x5 identity matrix
list_o_cols_to_use = [1 3 5];
used = matrix(:,list_o_cols_to_use)

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