How to delete two minimum elements in a vector?
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wonder how to delete two minimum elements in the vector and then calculate the mean value of new vector
the vector is like A=[ 70, 56 , 30, 10 , 83 , 78, 77, 90]
code should be flexibe enough to calculate for any vectors
2 Comments
Walter Roberson
on 20 Jan 2019
Suppose A had three values that were all (say) 9. All 3 of them are the minimum. What do you want to do in that situation?
Image Analyst
on 20 Jan 2019
Your request is very imprecise.
What would you return for
v = [1 1 1 2 2 2 3]
??? Would you return
- [1 2 2 2 3] (removing a pair of 1's), or
- [3] (removing all the 1's and all the 2's?
Accepted Answer
madhan ravi
on 20 Jan 2019
Edited: madhan ravi
on 20 Jan 2019
EDITED
n=2; % two smallest values
u=unique(A);
if numel(u)==1 || numel(u)==2
Result=[]
else
Result=mean(A(~ismember(A,u(1:n))))
end
6 Comments
madhan ravi
on 20 Jan 2019
Thank you sir Image Analyst edited the answer and sir Walter thank you for considering different situations.
More Answers (2)
Erik Keever
on 20 Jan 2019
Hmm. Perhaps,
% generate some random junk
x = round(10*rand([24 1]));
% sort array
[~, idx] = sort(x);
% sort the indices of the (N-2) largest elements, cutting the 2 smallest out and select subset
xTrimmed = x(sort(idx(3:end)));
I've taken that you mean to remove precisely two elements which are lexcographically smallest. My code breaks the degeneracy among multiple smallest values by choosing the first ones to occur in the array, such that among [4 1 1 0 4 4 4], the 0 and the first 1 will be removed. For large arrays, avoiding my lazy second sort() by building the subsets explicitly would be faster (removing one of two N log N sort procedures).
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