Find a random position in a vector where the value is zero

I have a vector with mix of complex numbers and zeros. I have to find a random position in the vector where the value is zero.

For example, in the given A matrix I should get any of the underlined value's vector position

A = [a b c 0 x 0 0 0 r 0 0 0 y q 0 p 0];

Answer 1

[Scott MacKenzie]

% test data (includes zeros and imaginary numbers)
A = [1i 4/1j 7 0 99 0 0 0 8*1j 0 0 0 8 9 0 -7 0];

% find indices of zeros in A
zeroIdx = find(A==0);

% pick one of the zeros at random (display index)
randomIdx = zeroIdx(randi(length(zeroIdx),1))

randonIdx = 6

Answer 2

[Chunru]

% Generate some randome data with zeros
n = 10;
a = randn(1, n);
k = randperm(n, round(n/2));
a(k) = 0;
a

a = 1×10

0 0 -1.5217 0 -1.5143 -0.0588 0 -0.0439 0 -1.0513

% find zeros
idx = find(a==0);

% randomly pick from idx
pick = randperm(length(idx), 1)

pick = 4

a(idx(pick))

ans = 0