用java帮我写一个推荐算法
时间: 2023-03-01 21:03:48 浏览: 61
当然,可以帮您写一个简单的推荐算法的 Java 代码。这里是一个基于用户的协同过滤算法,它基于用户的历史行为来生成推荐。
以下是 Java 代码:
```
import java.util.*;
public class Recommendation {
public static void main(String[] args) {
Map<String, Map<String, Double>> data = new HashMap<>();
data.put("User1", new HashMap<>());
data.get("User1").put("Item1", 5.0);
data.get("User1").put("Item2", 4.0);
data.get("User1").put("Item3", 2.0);
data.put("User2", new HashMap<>());
data.get("User2").put("Item2", 5.0);
data.get("User2").put("Item3", 3.0);
data.get("User2").put("Item4", 4.0);
data.put("User3", new HashMap<>());
data.get("User3").put("Item1", 4.0);
data.get("User3").put("Item3", 5.0);
data.get("User3").put("Item4", 3.0);
data.put("User4", new HashMap<>());
data.get("User4").put("Item1", 2.0);
data.get("User4").put("Item2", 3.0);
data.get("User4").put("Item4", 5.0);
Map<String, Double> similarities = new HashMap<>();
similarities.put("User2", 0.0);
similarities.put("User3", 0.0);
similarities.put("User4", 0.0);
for (Map.Entry<String, Map<String, Double>> entry1 : data.entrySet()) {
String user1 = entry1.getKey();
if (user1.equals("User1")) {
for (Map.Entry<String, Map<String, Double>> entry2 : data.entrySet()) {
String user2 = entry2.getKey();
if (!user1.equals(user2)) {
double dotProduct = 0.0;
double magnitude1 = 0.0;
double magnitude2 = 0.0;
Map<String, Double> user1Data = entry1.getValue();
Map<String, Double> user2Data = entry2.getValue();
for (Map.Entry<String, Double> innerEntry1 : user1Data.entrySet()) {
String item = innerEntry1.getKey();
double user1Rating = innerEntry1.getValue();
if (user2Data.containsKey(item)) {
double user2Rating = user2Data.get(item);
dotProduct
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