How to calculate the similarity of two objects?

Question

Algorithms

There are two objects A and B, they can be represented as two arrays that consist of 5 elements. Each element contains data of a certain type, the data type in the A[0] element of the array is the same as in B[0], i.e. these elements can be compared with each other. Suppose we somehow calculate that the data in element 0 is like 40%, the data in element 1 is like 90%, and so on. And then we have similarity data for each element. How can one, having this data, calculate how similar both objects are?

Answer 1

Cartesian distance = root sum of squared element deviations, Hamming distance = number of elements with deviation > delta.

Answer 2

Arrays are considered as vectors. Two ways: subtraction and correlation (product)
1) There are several types of vector difference, this is called the difference norm. One of the options - see above (cartesian distance).
2) We normalize the vectors (i.e., divide by the maximum possible length), then multiply the pairs and sum. With this method, the answer 1 means a match, -1 - the opposite.