Remove users/items ??

[johannbuscail]

Hey,
First, thanks for providing this amazing files that helped me a lot.
I'm trying to create a recommendation system, and I was wondering how to change/remove user/items/ratings.
I've created this function to add stuff (they work):

# add a user
def addUsers(interactions, model, users=[], user_dict={}, epoch=5, n_jobs=4):
    '''
    Adds ratings for a user
    Required Input -
        - interactions: the matrix containg each ratings for a user/item
        - model: the lightfm model
        - users: All the user ids of the new users
        - user_dict: Dictionary type output containing item_id as key and item_name as value
        - epoch = number of epochs to run
        - n_jobs = number of cores used for execution

    Expected Output -
        - interactions: The new matrix containing the new user
        - model: The new model trained with the new user
    '''
    for user_id in users:
        interactions.loc[user_id] = 0
        user_dict[user_id] = interactions.shape[0] - 1
    val = [[0 for y in range(interactions.shape[1])]
           for x in range(interactions.shape[0])]
    x = sparse.csr_matrix(val)
    model.fit_partial(interactions=x, epochs=epoch, num_threads=n_jobs)
    return interactions, user_dict, model

#add an item
def addItems(interactions, model, items=[], items_dict={}, epoch=5, n_jobs=4):
    for item_id, title in items:
        interactions[item_id] = 0
        items_dict[item_id] = title
    val = [[0 for y in range(interactions.shape[1])]
           for x in range(interactions.shape[0])]
    x = sparse.csr_matrix(val)
    model.fit_partial(interactions=x, epochs=epoch, num_threads=n_jobs)
    return interactions, items_dict, model

#add a rating
def addRatings(interactions,
               model,
               user_dict={},
               user=0,
               items=[0],
               ratings=[0],
               epochs=30,
               n_jobs=4):
    '''
    Adds ratings for a user
    Required Input -
        - interactions: the matrix containg each ratings for a user/item
        - model: the lightfm model
        - user_dict: Dictionary type output containing item_id as key and item_name as value
        - user: The user id
        - ratings: Array of ratings for each item -> [[ item, rating ]]
        - epoch = number of epochs to run 
        - n_jobs = number of cores used for execution

    Expected Output -
        - interactions: The new matrix containing new ratings
        - model: The new model trained with new ratings
    '''
    for item, rating in ratings:
        interactions[item][user] = rating
        uindex = user_dict[user]
        val = []
        for user_index in range(interactions.shape[0]):
            val.append(interactions.loc[user].values if user_index ==
                       uindex else [0 for x in range(interactions.shape[1])])
        x = sparse.csr_matrix(val)
        model.fit_partial(interactions=x, epochs=epochs, num_threads=n_jobs)
    return interactions, model

All of them work !
But how can I do to remove a rating or a user.
I don't know how to do that because fit_partial method is made to add data and not to remove
And finally, I was asking myself if setting a rating to 0 would be the same as just removing it
Thanks in advance !