# User based Collaborative Filtering (with Python)

I am trying to understand how can I calculate the similarity between userid and itemid. Here is the user-based table.The table didn't have rating /score information.

userid | itemid1 | itemid2 | itemid3 ... | itemid10000

1 | 1 | 0 | 1 | 1

2 | 0 | 1 | 1 | 1

3 | 0 | 0 | 0 | 1

1)Can I still use KNN method (like manhattan distance or euclidean distance) and cosine similarity method to calculate the similarity score? If so,how can I get these scores as vector matrix.

2)Suppose we have itemid > 100,000,000, so the table is very sparse. So do we have any method to control sparse data to deal with collaborative filtering problems.