MATLAB: How to use unique function to get data only when the number in one row increases

data importfunction

Hello,
I am trying to figure out on how to extract data only when the number in one of the row increases; for example:
a = [1;1;1; 2;3;4;5;6;7;8;9;10;10;10;11;11];
b = rand(16,1);
c = [b,a]
1) i want to extract the b data only when the number in 'a' increases, which are 1, 2, 3, 4, 5, – 10 without taking the data when the number in a is the same.
2) The numbers in a will go back to 1 after it reaches 255, so i want the function to still take the data when the number goes back to 1. this means that only when the number in a are the same in consequtive order then only you remove the repetition
i appreciate your help in this, please let me know if my question is not clear.

Best Answer

>> [a [true;diff(a)>0]]
ans =
   1     1
   1     0
   1     0
   2     1
   3     1
   4     1
   5     1
   6     1
   7     1
   8     1
   9     1
  10     1
  10     0
  10     0
  11     1
  11     0
>>
The "startover" case depends somewhat on how the series is defined; in the simplest case I think it would simply be
>> a=[a;a(1:5)];  % sample dataset w/ reset...
>> [a [true;diff(a)~=0]].'
ans =
Columns 1 through 15
   1     1     1     2     3     4     5     6     7     8     9    10    10    10    11
   1     0     0     1     1     1     1     1     1     1     1     1     0     0     1
Columns 16 through 21
  11     1     1     1     2     3
   0     1     0     0     1     1
>>
Or,
>> find([true;diff(a)~=0]).'
ans =
   1     4     5     6     7     8     9    10    11    12    15    17    20    21
>>
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