Counting consecutive negative numbers in an array

Hello, I need to find how many times consecutive negative numbers are in the array. For example:

v = [11 2 3 -1 -2 1 -1 -1 -3 1 3 -1];

The answer must be: 3

Thank you

Answer 1

[Bruno Luong]

length(strfind([false v<0],[0 1]))

or

sum(diff([false v<0])==1)

[BN]

Thank you...

I don't know why the answer is 2! I need 3. I think it doesn't count last -1 values. any idea?

Thank you so much again

[Bruno Luong]

How do you get 2?

>> v= [11 2 3 -1 -2 1 -1 -1 -3 1 3 -1]

v =

    11     2     3    -1    -2     1    -1    -1    -3     1     3    -1

>> length(strfind([false v<0],[0 1]))

ans =

     3

>> sum(diff([false v<0])==1)

ans =

     3

[BN]

Thank you so much. I forgot to use the clear command then try the code. After that, your code works very well.

Thank you it is really helpful for me