dataframe 篩選所需行

import pandas as pd
data= pd.read_csv('path',names = ['user_id','item_id','rating','timestamp'])

user_cnt = data.groupby(['user_id']).size().to_frame('user_count').reset_index()
user_filter_id = user_cnt[user_cnt['user_count']>=10]['user_id'].tolist()
data_filter = data[data['user_id'].isin(user_filter_id)]

item_cnt = data.groupby(['item_id']).size().to_frame('item_count').reset_index()
item_filter_id = item_cnt[item_cnt['item_count']>=10]['item_id'].tolist()

data_filter_item = data_filter[data_filter['item_id'].isin(item_filter_id)]