协同过滤,英文名Collaborative filtering,算法wiki上有详细介绍。
数据是来自MovieLens,地址:ml-100k.zip
Matlab Code分三个部分:
1.Loaddata.m,由于userSim计算耗时,这里用load userSim代替。
- clear;clc;
- [~, ~, raw] = xlsread('D:\My Documents\MATLAB\MovieLens\data.xlsx','u_data','A2:D100001');
- raw(cellfun(@(x) ~isempty(x) && isnumeric(x) && isnan(x),raw)) = {''};
- %% Replace non-numeric cells with NaN
- R = cellfun(@(x) ~isnumeric(x) && ~islogical(x),raw); % Find non-numeric cells
- raw(R) = {NaN}; % Replace non-numeric cells
- %% Create output variable
- data = reshape([raw{:}],size(raw));
- %% Allocate imported array to column variable names
- userId = data(:,1);
- itemId = data(:,2);
- rating = data(:,3);
- timestamp = data(:,4);
- %% Clear temporary variables
- clearvars data raw R;
- [~, ~, raw] = xlsread('D:\My Documents\MATLAB\MovieLens\data.xlsx','u_item','A2:B1683');
- raw(cellfun(@(x) ~isempty(x) && isnumeric(x) && isnan(x),raw)) = {''};
- cellVectors = raw(:,2);
- raw = raw(:,1);
- %% Create output variable
- data = reshape([raw{:}],size(raw));
- %% Allocate imported array to column variable names
- movieId = data(:,1);
- movieTitle = cellVectors(:,1);
- %% Clear temporary variables
- clearvars data raw cellVectors;
- format long;
- s=cell(0,0);
- unique_userId=unique(userId);
- nums_of_unique_userId=length(unique_userId);
- for user_index=1:nums_of_unique_userId;
- example_userId=unique_userId(user_index);
- example_userIds_itemId=itemId(userId==example_userId);
- example_userIds_rating=rating(userId==example_userId);
- nums_of_example_userIds_itemId=length(example_userIds_itemId);
- example_userId_meanRating=mean(example_userIds_rating);
- s{1,user_index}=example_userId;
- s{2,user_index}=example_userIds_itemId;
- s{3,user_index}=example_userIds_rating;
- s{4,user_index}=nums_of_example_userIds_itemId;
- s{5,user_index}=example_userId_meanRating;
- end
- % 计算example_userID的rating平均值example_userIds_meanRating
- % user_index=1;
- % example_userId=unique_userId(user_index);
- % example_userIds_meanRating=0;
- % example_userIds_rating=s{3,user_index};
- % example_userId_meanRating=mean(example_userIds_rating);
- load userSim;
- % 找出用户u,n相同的item和对应的rating——sameitemId_both_un矩阵包括same itemId及u,n对应的rating
- % userSim=zeros(nums_of_unique_userId,nums_of_unique_userId);
- % for u=1:nums_of_unique_userId
- % for n=1:nums_of_unique_userId
- % % u=100;n=200;
- % nums_of_us_itemId=s{4,u};
- % nums_of_ns_itemId=s{4,n};
- % us_meanRating=s{5,u};
- % ns_meanRating=s{5,n};
- % us_itemId=s{2,u};
- % ns_itemId=s{2,n};
- % us_rating=s{3,u};
- % ns_rating=s{3,n};
- %
- % nums_of_sameitemId_both_un=0;
- % sameitemId_both_un=[];
- % for us_itemId_index=1:nums_of_us_itemId
- % for ns_itemId_index=1:nums_of_ns_itemId
- % if us_itemId(us_itemId_index)==ns_itemId(ns_itemId_index),
- % nums_of_sameitemId_both_un=nums_of_sameitemId_both_un+1;
- % sameitemId_both_un=[sameitemId_both_un;us_itemId(us_itemId_index),us_rating(us_itemId_index),ns_rating(ns_itemId_index)];
- % end
- % end
- % end
- %
- % %计算用户u,n之间皮尔逊相关系数(pearon correlation coefficient)——userSim(u,n)
- % part1=0;
- % part2=0;part3=0;
- % for sameitemId_both_un_index=1:nums_of_sameitemId_both_un
- % part1=part1+(sameitemId_both_un(sameitemId_both_un_index,2)-us_meanRating)*(sameitemId_both_un(sameitemId_both_un_index,3)-ns_meanRating);
- % part2=part2+(sameitemId_both_un(sameitemId_both_un_index,2)-us_meanRating)^2;
- % part3=part3+(sameitemId_both_un(sameitemId_both_un_index,3)-ns_meanRating)^2;
- % end
- %
- % part2=max(part2,1e-3);
- % part3=max(part3,1e-3);
- % userSim(u,n)=part1/(sqrt(part2)*sqrt(part3));
- % end
- % end
2.函数movie_to_recommend_Func.m 这一段程序就不贴出来了,需要的可以发我邮件:taowenwu@gmail.com
3.主程序main.m
- userId=4;
- movie_to_recommend_Func(movieId,movieTitle,s,userSim,userId)
Output结果:
- >> main
- 用户userId=4推荐的电影有:
- 电影名:Toy Story (1995) 评分:4.6257
- 电影名:Get Shorty (1995) 评分:4.5329
- 电影名:Shanghai Triad (Yao a yao yao dao waipo qiao) (1995) 评分:4.3333
- 电影名:Twelve Monkeys (1995) 评分:4.3333
- 电影名:Babe (1995) 评分:4.3333
- 电影名:Dead Man Walking (1995) 评分:4.3333
- 电影名:Richard III (1995) 评分:4.3333
- 电影名:Usual Suspects, The (1995) 评分:4.3333
- 电影名:Mighty Aphrodite (1995) 评分:4.3333
- 电影名:Postino, Il (1994) 评分:4.3333
- 电影名:Mr. Holland's Opus (1995) 评分:4.3333
- 电影名:French Twist (Gazon maudit) (1995) 评分:4.3333
- 电影名:From Dusk Till Dawn (1996) 评分:4.3333
- 电影名:White Balloon, The (1995) 评分:4.3333
- 电影名:Antonia's Line (1995) 评分:4.3333
- 电影名:Angels and Insects (1995) 评分:4.3333
- 电影名:Muppet Treasure Island (1996) 评分:4.3333
- 电影名:Braveheart (1995) 评分:4.3333
- 电影名:Taxi Driver (1976) 评分:4.3333
- 电影名:Rumble in the Bronx (1995) 评分:4.3333
- >>