MATLAB: Select nearest non zero value in column

matrixnearest

Hi, I have a matrix of which the last column consists mainly of zeros and an occasionally non zero value. In a For loop I use each loop the next row for calculations, but for the last column I want to select the closest non zero value in that column. How should I do that? Thanks in advance!

Best Answer

b = [0; 0; 0; 2; 0; 0; 0; 0; 0; 3; 0]
nearestfun = @(b) interp1(find(b),b(b~=0),(1:length(b))','nearest','extrap');
closest = 0.5*(nearestfun(b) + flip(nearestfun(flip(b))))

Related Solutions

MATLAB: Subtract each column of matrix until -3 is finished

I am curious too. Let me guess.

a=0:4;
b=-3; % b is an integer, positive or negative
c=zeros(size(a));
ind=find(a,1);
c(ind:ind+abs(b)-1)=-1;
a=a+c
a =
     0     0     1     2     4

Updated for a generic solution

b = [0 2 1 2 3]
remainder=-6;
ind=find(b);
while remainder<0 && ~isempty(ind)
    if length(ind)<=abs(remainder)
        b(ind)=b(ind)-1
        remainder=remainder+length(ind)
        ind=find(b);
    else
        for k=1:abs(remainder)
            b(ind(k))=b(ind(k))-1
            remainder=remainder+1
        end
    end
end
b =
     0     2     1     2     3
b =
     0     1     0     1     2
remainder =
    -2
b =
     0     0     0     1     2
remainder =
    -1
b =
     0     0     0     0     2
remainder =
     0

MATLAB: How to convert A=[1 3 2] to B= [ 1 0 0;0 0 3;0 2 0]

A=[1 3 2];
n=numel(A)
idx=sub2ind([n n],A,1:n)
B=zeros(n)
B(idx)=A

Best Answer

Related Solutions

MATLAB: Subtract each column of matrix until -3 is finished

MATLAB: How to convert A=[1 3 2] to B= [ 1 0 0;0 0 3;0 2 0]

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