MATLAB: Mean value of array between values

mean valuemean value between values

Hi guys,

I need your help, I need to know a mean value of array between values (without max and min), for example:

a = [1 2 ; 3 4 ; 5 6]

max(A)=6

min(A)=1

Equation: (2 + 3 + 4 + 5)/4

I thought in something like:

( a(i)-max(a)-min(a) )/4

But that's wrong.

Please help me.

Best Answer

Yes, your thought is right

 mean_value_ex = (sum(a(:))-(max(a(:))+min(a(:)))/ (numel(a)-2))

Related Solutions

MATLAB: Compare all elements of a vector against each other

    relativeDiffs = abs( ( v - v' ) ) ./ v;  % R2016b syntax only
    indicatorMatrix = relativeDiffs <= 0.1;

will give you an indicator matrix of values to delete. Obviously you would ignore the leading diagonal as this is each value against itself. The values are normalised against the original v by row so the upper right triangle and lower left triangle will differ by the fact that e.g.

(3.5 - 2.4) / 2.4 ~= (3.5 - 2.4) / 3.5

You will get both of these answers from the relativeDiffs matrix. In some cases only one of these will highlight in the final indicator matrix as being < 10%.

relativeDiffs = abs( bsxfun( @minus, v, v' ) ) ./ v

should work for pre R2016b syntax.

MATLAB: Finding Middlemost row in a matrix

Perhaps - a bold guess:

meanValue = (min(A(:, 1:2)) + max(A(:, 1:2))) / 2;
dist      = sum((A(:, 1:2) - meanValue).^2, 2);   % >= 2016b: Auto-Expand
% With older Matlab versions:
% dist = sum(bsxfun(@minus, A(:, 1:2), meanValue).^2, 2)
[minDist, minIndex] = min(dist)
midA      = A(minIndex, :)

For your example:

% The center between the minimal and maximal points:
meanValue = [9.0755, 4.7075]
% (Squared) Euclidean distances of A(:, 1:2) to this point:
d = sum((A(:, 1:2) - meanValue).^2, 2)
% Minimal distance:
[minDist, minIndex] = min(d);
minIndex = 19
% Or do you want multiple outputs, if the minimal distance occurs
% multiple times?
??? minDist  = min(d);
??? minIndex = find(d == minDist);

But perhaps you look for something else. Unfortunately you do not provide a mathematical definition of what you want, although you have been asked repeatedly.

Best Answer

Related Solutions

MATLAB: Compare all elements of a vector against each other

MATLAB: Finding Middlemost row in a matrix

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