Change sequence of consecutive trues to falses, in logical array

Hello guys!

I would like to find a fast procedure to change from true to false the consecutive trues in a logical array excluding only the first and the last true in the sequence.

For instance:

x=[true;false;false;true;true;true;true;true];

Desired output array should be:

output=[true;false;false;true;false;false;false;true];

Hope the question is clear.

Thank you!

Answer 1

[Bruno Luong]

x=[true;false;false;true;true;true;true;true;false;true]'

x = 1×10 logical array
   1   0   0   1   1   1   1   1   0   1

x & ~([false,x(1:end-1)]&[x(2:end),false])

ans = 1×10 logical array
   1   0   0   1   0   0   0   1   0   1

Answer 2

[Chunru]

x=[true;false;false;true;true;true;true;true]'

x = 1×8 logical array
   1   0   0   1   1   1   1   1

output = x;
dx = diff(x(1:end-1))

dx = 1×6

-1 0 1 0 0 0

output1 = output(2:end-1);
output1(output1 & (dx==0)) = false;
% Desired output array should be:
output(2:end-1) = output1;
output

output = 1×8 logical array
   1   0   0   1   0   0   0   1

% Desired
[true;false;false;true;false;false;false;true]'

ans = 1×8 logical array
   1   0   0   1   0   0   0   1

[Enrico Gambini]

Thank you for the answer!

It does not work if a false is present after the last true of each sequence, for instance, if I had a vector like this:

x=[true;false;false;true;true;true;true;true;false;true]'

x = 1×10 logical array
   1   0   0   1   1   1   1   1   0   1

output = x;
dx = diff(x(1:end-1))

dx = 1×8

-1 0 1 0 0 0 0 -1

output1 = output(2:end-1);
output1(output1 & (dx==0)) = false;
% Desired output array should be:
output(2:end-1) = output1;
output

output = 1×10 logical array
   1   0   0   1   0   0   0   0   0   1

%Desired should be
[1,0,0,1,0,0,0,1,0,1]

ans = 1×10

1 0 0 1 0 0 0 1 0 1

I really need to automate this procedure and be sure it is robust, since I am dealing with very large array.

Thank you