How to solve "Index exceeds matrix dimensions" error?

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nfllover
nfllover 2012-2-20
My question might be simple for most of you. Basically, I would like to delete a row of a matrix where a value of an element in column 6 is zero. In doing so, I run the following command.
load filename.txt;
for i = 1:length(filename)
if filename(i,6) = 0;
filename(i,:) = [];
end
end
However, the error message comes up saying that "Index exceeds matrix dimensions.". I don't understand why it exceeds the dimension because I have already specified that i = 1 to the length of the matrix. Any help on this would be appreciated. Thank you.

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采纳的回答

Walter Roberson
Walter Roberson 2012-2-20
After you do the first deletion, the array is no longer as long as it used to be. The "for" limits are determined when the "for" is first encountered and are not adjusted at run-time.
(complete) Adjusted code:
load filename.txt
filename(filename(:,6) == 0, :) = [];

更多回答（2 个）

Oleg Komarov
Oleg Komarov 2012-2-20
Because you're shrinking filename if the condition is verified.
Once you delete a row, the length of filename is one unit smaller but the loop is still setup from 1 to initial dimension of filename.
nfllover
nfllover 2012-2-20
Thank you very much for your help. I have now solved the problem.

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