if command for finding more than three identical numbers in a variable

hi, I need an if condition with the following command. if there are more than three consecutive identical numbers in this matrix then give me an ok signal if not then give me a false signal.

example:

v=[8,8,8,9,5,5,8,8,1];

if there are more than 3 consecutive identical numbers in v (8,8,8) then give me an ok signal otherwise give me a false signal

How can I translate the above command into a matlab command. any kind is appreciated. thanks

[the cyclist]

Do you need 3 or more consecutive, or more than 3 consecutive?

Answer 1

[the cyclist]

You could download runlength from the File Exchange, and then do

max(runlength(v,Inf))>3

Other syntaxes with that function will also give the correct answer.

If you have a very large vector, or many of them, you might consider getting Jan Simon's RunLength instead.

Answer 2

[Guillaume]

You can use strfind (which despite the name also works with numbers) to find a [0 0] sequence in the diff of your vector (diff is [0 0] when three consecutive numbers are identical):

oksignal = ~isempty(strfind(diff(v), [0 0]))

Answer 3

[Roger Stafford]

You can devise your own test:

   if any(diff([0,find(diff(v)~=0),size(v,2)])>3)
     ...