Get difference between array values

Hello, I have an one column array (see below) with logical 0 and 1. I want to get the difference between each value to detect a jump from 0 to 1 and vice versa. I tried:

find(diff(test(:,1))>0.8)

but everytime I get an error named:

Subscript indices must either be real positive integers or logicals.

whos test:

 Name         Size            Bytes  Class    Attributes

test      2420x1              2420  uint8

I also tried to convert test to logical or int but the problem still exists. Can someone help?

Answer 1

[Stephen23]

You have a variable named diff. Delete that variable.

You might like to check all of these:

which test -all
which diff -all
which find -all

Answer 2

[leonidas86]

Okay thanks Stephen!!

Answer 3

[dpb]

You can't store the difference from 1 to 0 in an unsigned integer; is there a reason you can't just use default double for test? You must use a signed integer, however.

Also, there's no need for the (:,1) subscript expression on a vector, and since the values are integer logicals, there's no need for the >0.8.

ipos=find([0; diff(test)]==10;     % positive locations; augment to keep count same as original length
ineg=find([0; diff(test)]==-10;    % ditto for negative

[leonidas86]

With:

ipos=find([0 diff(test)]==1);

i get the following error

Error using horzcat
Dimensions of matrices being concatenated are not consistent.

[Stephen23]

If test is a column vector then you need to use a semi-colon:

[0;diff(test)]

[dpb]

Yeah, intended to fix and forgot...good catch.