How to replace some values in a matrix?

Question

aditya sahu 2017-5-1

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评论： Image Analyst 2017-5-1

I have x=16 * 16 matrix of double values. i need to figure out consecutive values of 'x' which are less than 150 and replace them with the original value plus(+) 8.

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Answer 1

Stephen23 2017-5-1

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编辑：Stephen23 2017-5-1

在 MATLAB Online 中打开

Just use a logical index:

>> x = randi(200,16,16);
>> idx = x<150;
>> x(idx) = x(idx)+8;

Very basic MATLAB operations, such as logical indices, as introduced in the Getting Started tutorials, which are highly recommended for all beginners:

https://www.mathworks.com/help/matlab/getting-started-with-matlab.html

https://www.mathworks.com/matlabcentral/answers/228557-experts-of-matlab-how-did-you-learn-any-advice-for-beginner-intermediate-users

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Stephen23 2017-5-1

编辑：Stephen23 2017-5-1

@aditya sahu: please explain the requirements with some example input and output data, because it is not clear to me what exactly you want. Why is 56 ignored, even though it is less than 150?

Image Analyst 2017-5-1

How are you defining consecutive? MATLAB goes row by row (down rows), then over to the next column and down its rows. Is that your definition? If so, then is the last element in column 2 consecutive with the first element in column 3?

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