在数据集中查找一行并复制到java中的另一个文件

我正在寻找一个小的代码片段，它将在第一列中找到多少个特定数字的单元格，并将1/4行（所有行）剪切到另一个文件中。例如，我在一个文件中有以下内容：

    //1. Based on my file path
    String filePath = "c:/mydatafile.txt";
    //2. I will reference the file path using "File" class
    File myTxtFile = new File(filePath);
    //3. Then BufferedReader to read the file
    BufferedReader bufferedReader = new BufferedReader(new FileReader(myTxtFile));
    //4. Start reading the file
    //You would like to have a variable to evaluate each line in your file
    String line = null;
    //StringBuilder to take the characters I want and save them to this
    StringBuilder appender = new StringBuilder();
    //Then loop...
    while ((line = bufferedReader.readLine()) != null) {
        //Evaluate the current line being read by the bufferedReader
        //You can use whatever you feel comfortable here: regex (matches), tokenizer, startsWith... but you need to think this
        if (condition) {
            appender.append(myVal);
        }
    }

    //Close the reader
    bufferedReader.close();

    //At the end I'll have my stringbuilder "appender" with the information I want and the only thing I would do is:
    String targetFile = "c:/mynewfile.txt";
    File myNewFile = new File(targetFile);

    BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(myNewFile));
    bufferedWriter.write(appender.toString());
    //Close the writer
    bufferedWriter.close();

dataset.txt： 代码将在第一列中找到多少

0

，并将1/4行带到另一个文件，我得到如下文件：

myFile.txt： 我的代码：

publicstaticvoidmain（字符串[]args）{
字符串in=“File.txt”；
String out=“File_new.txt”；
转换（输入、输出）；
}
私有静态void转换（字符串输入路径、字符串输出路径）{
试一试{
BufferedReader=new BufferedReader（new FileReader（inPath））；
BufferedWriter writer=新的BufferedWriter（新文件写入程序（输出路径））；
弦线；
而（（line=reader.readLine（））！=null）{
字符串[]aaa=line.split（“”）；
字符串换行=”；
如果（aaa[0]。等于（“0”））
对于（int i=0；i

while

内部的实现应该是什么样子？

---

我做了这样一件事：这个函数将行写入一个新文件，从0开始，现在我如何在复制到新文件后删除这一行？

首先，如果第一个字符是0，如果我正确理解您的问题，您只需要执行代码。我会这样做：

while(has next character) {
     while (first character is != 0) {
         writer.print(...);
         ...;
     }
}

这只是您试图完成的任务的伪代码。请试着自己写这篇文章，如果你写不出来，请进行编辑。希望这是有帮助的

编辑**

执行此操作的代码如下所示：

while(reader.hasNext()) {
     while (reader.nextDouble() == 0.0) {
         writer.print(reader.nextLine());
     }
}

---

不确定我是否理解你的问题，但我会做以下几点：

    //1. Based on my file path
    String filePath = "c:/mydatafile.txt";
    //2. I will reference the file path using "File" class
    File myTxtFile = new File(filePath);
    //3. Then BufferedReader to read the file
    BufferedReader bufferedReader = new BufferedReader(new FileReader(myTxtFile));
    //4. Start reading the file
    //You would like to have a variable to evaluate each line in your file
    String line = null;
    //StringBuilder to take the characters I want and save them to this
    StringBuilder appender = new StringBuilder();
    //Then loop...
    while ((line = bufferedReader.readLine()) != null) {
        //Evaluate the current line being read by the bufferedReader
        //You can use whatever you feel comfortable here: regex (matches), tokenizer, startsWith... but you need to think this
        if (condition) {
            appender.append(myVal);
        }
    }

    //Close the reader
    bufferedReader.close();

    //At the end I'll have my stringbuilder "appender" with the information I want and the only thing I would do is:
    String targetFile = "c:/mynewfile.txt";
    File myNewFile = new File(targetFile);

    BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(myNewFile));
    bufferedWriter.write(appender.toString());
    //Close the writer
    bufferedWriter.close();

也许这会对你的寻找有所帮助。快乐编码

while（（line=reader.readLine（））！=null）{

String[]aaa=line.split（“”）；
字符串换行=”；
如果（aaa[0]。等于（“0”））
对于（int i=0；i

所以不写代码。请告诉我们您的尝试。如果您了解java，只需阅读0或1的行监视，然后复制到新文件，这很容易。如果你不懂java，最好的解决办法就是在网上阅读任何手册。然后复制你的代码，人们会帮助你。现在你有了文件，下一步是计算一行，例如，尝试以下操作：

while(reader.hasNext()) {
     while (reader.nextDouble() == 0.0) {
         writer.print(reader.nextLine());
     }
}

    //1. Based on my file path
    String filePath = "c:/mydatafile.txt";
    //2. I will reference the file path using "File" class
    File myTxtFile = new File(filePath);
    //3. Then BufferedReader to read the file
    BufferedReader bufferedReader = new BufferedReader(new FileReader(myTxtFile));
    //4. Start reading the file
    //You would like to have a variable to evaluate each line in your file
    String line = null;
    //StringBuilder to take the characters I want and save them to this
    StringBuilder appender = new StringBuilder();
    //Then loop...
    while ((line = bufferedReader.readLine()) != null) {
        //Evaluate the current line being read by the bufferedReader
        //You can use whatever you feel comfortable here: regex (matches), tokenizer, startsWith... but you need to think this
        if (condition) {
            appender.append(myVal);
        }
    }

    //Close the reader
    bufferedReader.close();

    //At the end I'll have my stringbuilder "appender" with the information I want and the only thing I would do is:
    String targetFile = "c:/mynewfile.txt";
    File myNewFile = new File(targetFile);

    BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(myNewFile));
    bufferedWriter.write(appender.toString());
    //Close the writer
    bufferedWriter.close();

     String[] aaa = line.split(" ");
     String newLine = "";                                  
     if(aaa[0].equals("0"))
     for(int i =0; i < aaa.length; i++)
     newLine += aaa[i]+' ';
     newLine += '\n';                                       
     writer.write(newLine);  


    }