I need help finding the center of an n * n array. TA couldn't figure it out

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Blair Hall 2017-10-27

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评论： Patricio 2023-1-23

Assign middleElement with the element in the center of squareArray. Assume squareArray is always an n x n array, where n is odd. Hint: elementIndex should be rounded to an integer. Ex: If squareArray is [1, 2, 3; 4, 5, 6; 7, 8, 9], then middleElement is 5.

function middleElement = FindMiddle(squareArray) 
% FindMiddle: Return the element in the center of squareArray
%   Inputs: squareArray - n x n input array, where n is odd
%
%   Outputs: selectedData - center element of squareArray
      % Assign elementIndex with location of middle row/col
      % Hint: Use the size() function to deterimine the dimension of squareArray
      elementIndex = size(squareArray); %3.5 /2
      % Assign middleElement with the center element of squareArray
      middleElement = squareArray(elementIndex);
  end

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Jan 2018-1-30

@Jose Garcia: You have set a flag with the contents: "Gives the wrong answer when inputting values". It is not clear, which code you mean and what you observe. Please post a comment and add details. The flags are thought to inform admins and editors about messaged, which might violate the terms of use, e.g. if they are rude or spam.

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采纳的回答

Image Analyst 2017-10-27

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https://ww2.mathworks.cn/matlabcentral/answers/363518-i-need-help-finding-the-center-of-an-n-n-array-ta-couldn-t-figure-it-out#answer_288009

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Like this:

m = [1, 2, 3; 4, 5, 6; 7, 8, 9]
middleElement = m(ceil(numel(m)/2))

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Rik 2020-4-26

That's because it isn't a function, it's a variable.

Image Analyst 2020-4-26

在 MATLAB Online 中打开

My answer does not have the word squareArray in it, so you didn't try my answer. Again, here is the complete solution:

% Case 1.  Returns 5.
m = [1, 2, 3; 4, 5, 6; 7, 8, 9]
middleValue = FindMiddle(m) 
% Case 2.  Returns 13.
m = [1, 2, 3, 4, 5; 6, 7, 8, 9, 10; 11, 12, 13, 14, 15; 16, 17, 18, 19, 20; 21, 22, 23, 24, 25]
middleValue = FindMiddle(m) 
% Case 3.  Like Case 2 but without commas. Returns 13.
m = [1 2 3 4 5;6 7 8 9 10; 11 12 13 14 15; 16 17 18 19 20;21 22 23 24 25]
middleValue = FindMiddle(m) 
function middleElement = FindMiddle(m)
	% Method 1:
	middleIndex = ceil(size(m, 1)/2);
	middleElement = m(middleIndex, middleIndex);
	% Method 2: (Commented out now)
	% middleElement = m(ceil(numel(m)/2))
end

If you want to replace m in FindMiddle, you can. I changed it to m since my code works for any size matrix, not just square ones.

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Mandy Downs 2021-1-28

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https://ww2.mathworks.cn/matlabcentral/answers/363518-i-need-help-finding-the-center-of-an-n-n-array-ta-couldn-t-figure-it-out#answer_608673

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function middleElement = FindMiddle(squareArray) 
% FindMiddle: Return the element in the center of squareArray
%   Inputs: squareArray - n x n input array, where n is odd
%
%   Outputs: selectedData - center element of squareArray
    
    % Assign elementIndex with location of middle row/col
    % Hint: Use the size() function to deterimine the dimension of squareArray
    elementIndex = size (squareArray);
    elementIndex = (elementIndex / 2) + 0.5;
    
    % Assign middleElement with the center element of squareArray
    middleElement = squareArray (elementIndex, elementIndex);
    middleElement = middleElement (1)
    
end