Find range between two array's indexes

Hello,

I have two arrays of different sizes and I Would like to find certain range between them, where the start index is from one array and ends with another array. For example:

A = [4192 23330 23342 29974 49089 49093 49096 55753 57035 57039]
B = [22780 48556 56522]

The desired output would be

C = [4192 22780; 29974 48556 ; 49096 56522]

Note that A and B can change in size, but array B is always the end point value.

Thanks, Max

[Stephen23]

Should the example really be this? :

C = [4192 22780; 29974 48556 ; 55753 56522]

Or if not, please explain why 49096 is selected, and not 55753.

Answer 1

[Stephen23]

Assuming that the rule really should pick the closest values from A that a re less than the values in B:

>> A = [4192 23330 23342 29974 49089 49093 49096 55753 57035 57039];
>> B = [22780 48556 56522];
>>
>> X = A(any(diff(bsxfun(@lt,A(:),B(:).')),2));
>> C = [X(:),B(:)]
C =
  4192   22780
 29974   48556
 55753   56522

[Max Bernstein]

Sorry for the mistake, but yes it should be the closest values from A that are less than B.

I got an error using your code:

>> X = A(any(diff(bsxfun(@lt,A(:),B)),2));
Error using bsxfun
Non-singleton dimensions of the two input arrays must match each other.

[Stephen23]

@Max Bernstein: this error happens because the vector B you are using is a column vector, whereas the vector B you gave in your example is a row vector. I fixed my code to work with both of these.

Answer 2

[Thorsten]

If you use that highest value that is still smaller than the corresponding B, you can write:

C = [A(arrayfun(@(i) find(A < B(i), 1, 'last'), 1:numel(B))); B]'

But this differs from your desired output. So what is the rule according to which you pick the values form A?

[Max Bernstein]

Sorry for the mistake, but yes it should be the closest values from A that are less than B.

Your answer works great, my desired output is:

C = [A(arrayfun(@(i) find(A < B(i), 1, 'last'), 1:numel(B))), B]'

replaced ; with ,