title: Euclidean Distance
body: <p>I have some problem understanding euclidean distance. I have two different entities and I want to measure the similarity between these entities.</p>
  
  <p>Lets suppose that entity A has 2 feature vectors and entity B has 1 feature vector only. How am I supposed to calculate the euclidean distance between these two entities in order to know the similarity?</p>
  
  <p>Thanks a lot.</p>