how to find n values that are closest to zero

I have a matrix of 50 x 50 with floating point values both positive and negative signs...i want to find n values lying on both sides that are closest to zero along with their indices ... please help

Answer 1

[Azzi Abdelmalek]

Look at this example: A is a matrix 5x5 and n=2

A=rand(5)-0.5
n=2
[~,idx]=sort(abs(A(:)))
B=A(idx)
[ii,jj]=ind2sub(size(A),idx(1:n))
out=[B(1:n) ii jj]

[studentambitious]

thanks for the reply ... can you please tell one more thing how i can access the first n values of vector B as B(ii,jj) then modify these values and put them back to their respective positions in the matrix form.

[Walter Roberson]

NewB = f(B);   %modify B
A(idx) = NewB;  %put them back where you got them in A

[studentambitious]

Thanks Walter

[studentambitious]

can we replace ~ in line [~, idx]=sort(abs(A(:))) with some other name???? how this NOT (~) symbol works here