how to choose right index

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imola
imola 2015-2-16
评论： imola 2015-2-16
Dear All,
I have this matrix X and this is the index for it. I want to take the row with 1 1 index to empty and plot the remind points, but I got wrong
Y =[1.7797 1.3341
1.5067 0.5390
1.0709 1.0732
1.2872 1.0745
0.3687 1.4166
0.4112 0.2333
1.4512 0.8961
1.9749 1.6645];
idx =[0 1
0 1
1 1
1 1
0 1
0 0
1 1
0 0];
m=8;
for i=1:1:m
if idx(i,1:1:end)==1
Y(i,:)=[]
end
m=size(Y,1)
end
plot(Y(:,1),Y(:,2),'.r');
I know my problem with the if condition, I don't know who to write it correct. Can anyone help me please.
Regards, imola
regards
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imola
imola 2015-2-16
sorry Geoff,
I change the question hopefully make it simple, I'm stuck here
if idx(i,1:1:end)==1
I think it is wrong, I want to generalize this formula to dim>2 if it succeed here.
Thanks for replying.
Regards
Image Analyst
Image Analyst 2015-2-16
You say "I have this matrix X" - what matrix X???? And if idx(i,1:1:end)==1 gives a vector. I think you want to use all().

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采纳的回答

Image Analyst
Image Analyst 2015-2-16
Perhaps you want this:
clc;
Y =[1.7797 1.3341
1.5067 0.5390
1.0709 1.0732
1.2872 1.0745
0.3687 1.4166
0.4112 0.2333
1.4512 0.8961
1.9749 1.6645];
idx =[0 1
0 1
1 1
1 1
0 1
0 0
1 1
0 0];
[rows, columns] = size(idx)
rowsToKeep = false(rows, 1);
for row=1:1:m
allOnes = all(idx(row, :));
if ~allOnes
rowsToKeep(row) = true;
end
end
rowsToKeep
extractedY = Y(rowsToKeep, :);
plot(extractedY(:,1), extractedY(:,2), 'r.-', 'MarkerSize', 20);
grid on;
  1 个评论
imola
imola 2015-2-16
Dear,
thank you very much for your answer. you really saved me. I understood what you did but I want to be sure so I can use the commends in future, so could you please explain it to me.
Many thanks,
Imola.

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更多回答（1 个）

Thorsten
Thorsten 2015-2-16
编辑：Thorsten 2015-2-16
Y = Y(sum(idx, 2) ~= 2, :);
plot(Y(:,1), Y(:,2), '.r')

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