# how to select two arrays from a group of four

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i have 4 arrays and i need to square each element then find the total. then the 2 arrays that have to lowest total get selected and assigned a value eg, u3
would love some help from a true matlab master

Thomas Satterly on 13 Nov 2019
To find the sum square of an array:
sumSquared = sum(array.^2);
If you have your arrays all together in a matrix:
% If each array is a colum of the matrix
sumSquaredEachArray = sum(matrix.^2, 1);
% If each array is a row of the matrix
sumSquaredEachArray = sum(matrix.^2, 2);
For finding the two lowest scores, let's assume that you have the scores in an array called "sumSquaredEachArray" (which would happen automatically if you have your arrays organized in a matrix)
% Get the order of lower to highest scores
[~, order] = sort(sumSquaredEachArray);
% Select the first two scores from the sorted order, which would be the lowest two
lowestTwoScores = order(1:2);
% Set those scores to "u3"
sumSquaredEachArrau(lowestScores) = u3;

#### 1 Comment

Lachlan Pemberton-Pigott on 14 Nov 2019
thanks this works perfect

R2019b

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