How to select specific elements in a matrix?

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Tin Nguyen
Tin Nguyen 2015-10-10
评论： the cyclist 2015-10-11
Say I have a 10x10 matrix
x =
17 24 1 8 15
23 5 7 14 16
4 6 13 20 22
10 12 19 21 3
11 18 25 2 9
And I want to select a certain element from each row in the matrix for example: I want elements from row 1 column 3, row 2 column 4, row 4 column 3, row 5 column 3 and turn those element into 0. I know I can do something like:
x(1,3)=0;
x(2,4)=0;
etc. But that is time-consuming. Is there a code that I can just write all that in one line? I thought it would be something like:
x=([1 2 3 4], [3 4 3 3])=0;

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回答（1 个）

the cyclist
the cyclist 2015-10-10
Yes, but you have to use "linear indices":
x = [
17 24 1 8 15
23 5 7 14 16
4 6 13 20 22
10 12 19 21 3
11 18 25 2 9]
linearIndices = sub2ind(size(x),[1 2 3 4], [3 4 3 3])
x(linearIndices) = 0
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Tin Nguyen
Tin Nguyen 2015-10-10
Thank you so much! That worked perfectly :) !
the cyclist
the cyclist 2015-10-11
The best form of thanks is accepting a solution that worked for you. (This rewards the person who helped you, and also may help future people with a similar question.)

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