Split array into groups of close numbers

Greetings,

Is there a built-in function in MATLAB to split an 1D array into groups of close numbers?

For example, I have an array

a = [1 2 3 10 11]

and want to split it into N = 2 groups. I expect to see something like

result{1} = [1 2 3]
result{2} = [10 11]

[Dyuman Joshi]

How do you define close numbers?

Where the difference between adjacent numbers in 1?

Answer 1

[Stephen23]

a = [1,2,3,10,11];
n = 2;
x = kmeans(a(:),n)

x = 5×1

2 2 2 1 1

c = accumarray(x,a(:),[],@(a){a})

c = 2×1 cell array
    {2×1 double}
    {3×1 double}

Answer 2

[Walter Roberson]

No -- because there is no rigourous meaning to what "close" means.

For example, in [1 3 5 7], surely 1 is not "close" to 7, but 5 is (probably) close to 7. Then 3 is "close" to 5, and 1 is "close" to 3. So are they all to be considered close as a group, even though 1 is "far" from 7 ?

Now, if the question were about dividing up into groups of consecutive values, then that would not be too difficult.

You could also use something like

N = 2;
a = [1 2 3 10 11]

a = 1×5

1 2 3 10 11

[g, centroids] = kmeans(a(:), N)

g = 5×1

1 1 1 2 2

centroids = 2×1

2.0000 10.5000