将映射字符串转换为java中的唯一int ID？

Question

什么是将数据从字符串转换为唯一的ID INT。例如

UserName, MovieType , year watched 
John , Comedy , 2000 
John , Comedy , 2012 
Alis , Comedy , 2005 
Alis, Animation , 2003 

TO

UserName, MovieType , year watched 
1, 4, 2000 
1, 4, 2012 
2, 4, 2005 
2,3,2003 

我当时就想，用户名和MovieType添加到设置以获得独特的名单最好的选择第一。然后为它们中的每一个创建一个Map。我现在的问题是，我如何使用2 Maps来读取和比较原始数据（表1）以创建新数据（表2）。假设我用地图>为表1

感谢

Answer 1

你可以看到这里的工作示例：

进口的java.util.HashMap; import java.util.Map;

public class MainClass { 

    private static final String [] dataArray = { "John , Comedy , 2000", 
         "John , Comedy , 2012", 
         "Alis , Comedy , 2005 ", 
         "Alis, Animation , 2003"}; 

    public static void main(String[] args) { 
     int wordIndex = 0; 
     Map<String, Integer> wordIndexMap = new HashMap<String, Integer>(); //Map to store Word and related index 
     Map<Integer, String> reverseWordMap = new HashMap<Integer, String>(); //Map to store index to word 
     String [] convertedArray = new String [dataArray.length]; 

     for(int index = 0; index < dataArray.length; index++) { 
      String [] tokens = dataArray[index].trim().split("\\s*,\\s*"); 
      StringBuilder convertedString = new StringBuilder(); 
      boolean dataEncountered = false; 
      for(int tokenIndex = 0; tokenIndex < tokens.length; tokenIndex++) { 
       if(dataEncountered) {      //Add ', ' only when something is added to the convertedString 
        convertedString.append(", "); 
       } 

       if(tokens[tokenIndex].matches("\\d+")) {  //To match the years like 2000, 2010 etc. This condition can be altered according to the requirement 
        convertedString.append(tokens[tokenIndex]); 
       } else { 
        if(wordIndexMap.get(tokens[tokenIndex]) == null) { 
         wordIndexMap.put(tokens[tokenIndex], ++wordIndex); 
         reverseWordMap.put(wordIndex, tokens[tokenIndex]); 
        } 
        convertedString.append(wordIndexMap.get(tokens[tokenIndex])); 
       } 
       dataEncountered = true; 
      } 
      convertedArray[index] = convertedString.toString(); 
     } 

     String [] reverseConvertedArray = new String[convertedArray.length]; 

     for(String data: convertedArray) { //Print the converted array 
      System.out.println(data); 
     } 

     for(int index = 0; index < convertedArray.length; index++) { 
      String [] data = convertedArray[index].trim().split("\\s*,\\s*"); 
      StringBuilder convertedString = new StringBuilder(); 
      boolean dataEncountered = false; 
      for(int arrayIndex = 0; arrayIndex < data.length; arrayIndex++) { 
       if(dataEncountered) { 
        convertedString.append(", "); 
       } 

       if(arrayIndex + 1 == data.length) {   //To ignore the last item of the String 
        convertedString.append(data[arrayIndex]); 
       } else { 
        convertedString.append(reverseWordMap.get(Integer.parseInt(data[arrayIndex]))); 
       } 
       dataEncountered = true; 
      } 
      reverseConvertedArray[index] = convertedString.toString(); 
     } 

     for(String data: reverseConvertedArray) {  //Print the reverse converted array 
      System.out.println(data); 
     } 
    } 

}