文件中的排序行取决于c#中文件本身的内容

Question

我的文件中的行内容格式如下：

Ref.,ID,Firstname,Secondname,City

这是我的文件：

1,4234,Firstname1,Secondname1,City1
2,5647,Firstname2,Secondname2,City2
3,1657,Firstname3,Secondname3,City3
4,3898,Firstname4,Secondname4,City4

现在我想按 ID 对其进行排序，然后将其再次放入文件中，如下所示：

3,1657,Firstname3,Secondname3,City3
4,3898,Firstname4,Secondname4,City4
1,4234,Firstname1,Secondname1,City1
2,5647,Firstname2,Secondname2,City2

注意：整行是一个字符串变量。

那么有没有办法做到这一点？

这是我的代码：

int counter = 0;
string ln; //Each line in file per loop   Ex:1,8957,Firstname,lastname,city

using (StreamReader file = new StreamReader(filePath))
{
    Console.WriteLine("Records in the file" + Environment.NewLine);

    Console.WriteLine("Ref,First name,Second name,City" + Environment.NewLine);

    while ((ln = file.ReadLine()) != null)
    {
        Console.WriteLine(ln + Environment.NewLine);

        /*
        So here i need to sort the lines in the file, which written hard coded in the file before spliting it.
        */

        //split the current line (comma separated) into array of strings with Ref,Id,first name, last name and city respectively
        listLineElements = ln.Split(',').ToList();

        //get city (4th elemnt in the array)
        Student student = new Student(listLineElements[0], listLineElements[1], listLineElements[2], listLineElements[3], listLineElements[4]);

        //for each line call addIndex to check whether index is new? or add it to the secondary index list?
        addIndex(student.getCity(), ln);

        counter++; //counter for the number of read lines
    }
    file.Close();
}

Answer 1

你可以这样做：

string[] lines = File.ReadAllLines(filePath);

string[] sortedLines = lines
    .Select(s => new
    {
        Line = s,
        SortKey = int.Parse(s.Split(',')[1])
    })
    .OrderBy(sl => sl.SortKey)
    .Select(sl => sl.Line)
    .ToArray();

File.WriteAllLines(filePath, sortedLines);

演示小提琴：https : //dotnetfiddle.net/g8M8nQ