关于数据中user_id,item_id重新编码的技巧

uids = sorted(out_df['user_id'].unique())
user2id = dict(zip(uids, range(1, len(uids) + 1)))
iids = sorted(out_df['item_id'].unique())
item2id = dict(zip(iids, range(1, len(iids) + 1)))

out_df['user_id'] = out_df['user_id'].apply(lambda x: user2id[x])
out_df['item_id'] = out_df['item_id'].apply(lambda x: item2id[x])
out_df = out_df.reset_index(drop=True)
out_df.head()