problem with randsample when array with one element

when vector has one element, the result of randsample is not correct for my problem. It returns a random number from 1 to that element.

for example:

n=[3]; 
x = randsample(n,1);

randsample returns x=1 or x=2 or x=3

but I want x=3 only

Answer 1

[Chad Greene]

Perhaps you want

n = 3; 

% get a random index no greater than the length of n:
ind = randsample(length(n),1); 

% take a random value from n: 
x = n(ind)

Answer 2

[Image Analyst]

What do you mean by "when vector has one element"??? WHAT vector? randsample will return 1 number randomly chosen from the vector 1 ..... n, which in your case is [1,2,3] so of course x will be either 1, 2, or 3. What did you expect? If you want x to be 3 or n, simply do this

x = n;

Answer 3

[Roger Stafford]

That's what it is supposed to return. Read the website:

   http://www.mathworks.com/help/stats/randsample.html

which states " y = randsample(n,k) returns a k-by-1 vector y of values sampled uniformly at random, without replacement, from the integers 1 to n."

Answer 4

[Aaron Schnydrig]

The question is quite old, but for the ones finding it over Google (like I did):

The simplest answer would be the following:

x = randsample(repmat(n, 2, 1), 1);

The repmat() function uses every value of your vector twice. Therefore, it will not change the probability of a certain element. However, it will make sure that your vector always has more than one element and is therefore used as a population.