java - 在 csv 文件中搜索列单词并将其替换为另一个值 java

Question

我有两个 csv 文件，主文件和外观文件。主文件包含这样的单词列表:

a,c,e,f
b,d,o,f

和look.csv包含两行，如下所示:

a,f,j
1,0,1

我想搜索 main.csv 的每个单词并在 Look.csv 中找到匹配项。如果存在匹配项，我将 main.csv 中的单词替换为 Look.csv 第 2 行中的值

我写了这段代码

public class lookup {
   public static void main(String args[]) throws FileNotFoundException
   {
       String word;
       Scanner main = new Scanner(new File("C:\\Users\\sa\\Desktop\\hotel2\\all.csv"));
       main.useDelimiter(",");           
       Scanner look=new Scanner (new File("C:\\Users\\sa\\Desktop\\comtedad.csv"));

       while (main.hasNext())
       {
           word=main.next()  ;

           while (look.hasNext()){
               if (main.next().equals(look.next())) {//code for replacing}
                   }
    }
               main.close();




  }}

当两个条目匹配时，如何访问look.scv的第二行？

Answer 1

在发布我的解决方案之前需要注意一些事项:

• 在读取文件时没有简单的方法来替换文件的内容，您必须创建一个新文件并在那里输出您需要的内容
• 如果你想替换值，那么这是使用 map 的好地方
• 您的代码意味着 look.csv 文件仅包含 2 行

以下内容将实现您正在寻找的内容，但同样，输出位于不同的文件中(如果您愿意，可以在之后重命名):

public class Main {

public static void main(String[] args) throws Exception {
    //1. create Scanners that will look through the CSV files
    Scanner main = new Scanner(new File("main.csv"));
    Scanner look = new Scanner(new File("look.csv"));

    //2. create the final CSV file that will contain both the replaced words and non-replaced words from main.csv
    FileWriter replaced = new FileWriter(createReplacedCsv());

    //3. store contents of look.csv in a Map
    Map<String, String> lookCsvWords = storeLookCsvInSet(look);

    //4. Store the contents of the file in a StringBuilder, so you can use the StringBuilder.deleteCharAt(int)
    // and .lastIndexOf(String) to delete the last comma
    StringBuilder builder = new StringBuilder();

    //5. keep track of the line we are on
    int line = 0;

    //6. iterate through main.csv and search for replaceable words, and write them to replaced.csv if they are found
    while (main.hasNext()) {

        //search the first line for replaceable chars
        String[] wordsInLine = main.nextLine().split(",");
        for (String word : wordsInLine) {
            if (lookCsvWords.containsKey(word) && line == 0) {
                word = lookCsvWords.get(word);
            }
            builder.append(word).append(",");
        }
        line ++;
        builder.deleteCharAt(builder.lastIndexOf(","));
        builder.append("\n");
    }

    //7. write the contents of the StringBuilder to the file
    replaced.write(builder.toString());
    replaced.close();
}

/*
 * Creates the replaced.csv file if it doesn't exist
 */
private static File createReplacedCsv() throws Exception {
    File replacedCsv = new File("replaced.csv");
    replacedCsv.createNewFile();
    return replacedCsv;
}

/*
 * Store the words within look.csv in a Map.
 * This method assumes that look.csv has only two lines
 */
private static Map<String, String> storeLookCsvInSet(Scanner lookScanner) throws Exception {
    Map<String, String> lookCsvWordMappings = new HashMap<String, String>();
    String[] line1Values = lookScanner.nextLine().split(",");
    String[] line2Values = lookScanner.nextLine().split(",");

    for (int i=0; i<line1Values.length; i++) {
        lookCsvWordMappings.put(line1Values[i], line2Values[i]);
    }
    return lookCsvWordMappings;
}

}