使用.Split（）方法遇到問題

Question

此代碼拋出異常，「索引超出了數組邊界」。不應該這樣簡單地將每個分割數據添加到指定的數組插槽中嗎？

while (input != null) 
{ 
    string[] splitInput = inputLine.Split(); 
    EmpNum = int.Parse(splitInput[0]); 
    EmpName = (splitInput[1]); 
    EmpAdd = (splitInput[2]); 
    EmpWage = double.Parse(splitInput[3]); 
    EmpHours = double.Parse(splitInput[4]); 
    inputLine = (myFile.ReadLine()); 
    Console.WriteLine("test {0},{1},{2}", EmpNum, EmpWage, EmpHours); 
} 

要澄清一點，我從有僱員數據（姓名，地址，營業時間，員工數量，工資）一個簡單的文本文件中讀取數據。

爲了清晰起見，我添加了我的整個主要方法。

using System; 
using System.IO; 

class Program 
{ 
static void Main() 
{ 

    //declare an array of employees 
    Employee[] myEmployees = new Employee[10]; 

    //declare other variables 
    string inputLine; 
    string EmpName; 
    int EmpNum; 
    double EmpWage; 
    double EmpHours; 
    string EmpAdd; 

    //declare filepath 
    string environment =   System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal) + "\\"; 

    //get input 
    Console.Write("\nEnter a file name in My Documents: "); 
    string input = Console.ReadLine(); 
    string path = environment + input; 
    Console.WriteLine("Opening the file..."); 

    //read file 
    StreamReader myFile = new StreamReader(path); 
    inputLine = (myFile.ReadLine()); 

    //split input 
    while (inputLine != null) 
    { 

     string[] splitInput = inputLine.Split(); 
     EmpNum = int.Parse(splitInput[0]); 
     EmpName = (splitInput[1]); 
     EmpAdd = (splitInput[2]); 
     EmpWage = double.Parse(splitInput[3]); 
     EmpHours = double.Parse(splitInput[4]); 
     Console.WriteLine("test {0},{1},{2}", EmpNum, EmpWage, EmpHours); 
    } 

    Console.ReadLine(); 
}//End Main() 
}//End class Program 

Answer 1

也許這個版本將是很好的加分:)認真不過我並不想在這裏炫耀 - 只是，即使它是一個學習的榜樣，如果你找到一份工作，並給出了任務編寫讀取CSV文件的代碼，例如，您不希望它崩潰並使您看起來很糟糕，因此您會親自了解一些步驟以使其更加健壯。

請注意 - 這不是嘗試開始辯論代碼示例的完美方式 - 只是試圖展示一些我知道有用的技巧。希望它有幫助。

  StreamReader myFile = new StreamReader("TextFile1.txt"); 
      int lineNumber = 0; 
      while (!myFile.EndOfStream) 
      { 
       // Read the next line. 
       string inputLine = myFile.ReadLine(); 
       lineNumber++; 

       // Extract fields line. 
       string[] splitInput = inputLine.Split(); 

       // Make sure the line has the correct number of fields. 
       if (splitInput.Length == 5) 
       { 
        // Parse and validate each field. 

        if (!int.TryParse(splitInput[0], out EmpNum)) 
        { 
         Console.WriteLine("could not parse int " + splitInput[0] + " on line " + lineNumber); 
         continue; 
        } 

        EmpName = (splitInput[1]); 

        EmpAdd = (splitInput[2]); 

        if(!double.TryParse(splitInput[3], out EmpWage)) 
        { 
         Console.WriteLine("could not parse double " + " on line " + lineNumber); 
         continue; 
        } 

        EmpHours = double.Parse(splitInput[4]); 

        if (!double.TryParse(splitInput[4], out EmpHours)) 
        { 
         Console.WriteLine("could not parse double: " + " on line " + lineNumber); 
         continue; 
        } 

        // Output 
        Console.WriteLine("test {0},{1},{2}", EmpNum, EmpWage, EmpHours); 
       } 
       else 
       { 
        Console.WriteLine("Expecting 5 items from split opertation but got " + splitInput.Length + " on line " + lineNumber); 
       } 
      } 
      myFile.Close(); 

TextFile1.txt

1 2 3 4 5 
6 7 8 f9 10 
11 12 

程序輸出

test 1,5,5 
could not parse double: on line 2 
Expecting 5 items from split opertation but got 2 on line 3 

Answer 2

檢查你的字符串，你可能不會得到輸入5種元素和分割方法提供了一些字符

更改inputLine.Split()到inputLine.Split(',')，如果你是用逗號

分離元件

您輸入的內容如「第一」，「第二」，「第三」，「第四」，「第五」

Answer 3

1）應該不是input是inputLine？

2）在使用它之前，爲每個數組元素添加一個空檢查。

而且我想，

while (input != null) 
    { 
     string[] splitInput = inputLine.Split(); 
     EmpNum = int.Parse(splitInput[0]); 
     EmpName = (splitInput[1]); 
     EmpAdd = (splitInput[2]); 
     EmpWage = double.Parse(splitInput[3]); 
     EmpHours = double.Parse(splitInput[4]); 
     inputLine = (myFile.ReadLine()); 
     Console.WriteLine("test {0},{1},{2}", EmpNum, EmpWage, EmpHours); 
    } 

應該

while (input != null) 
    { 
     inputLine = (myFile.ReadLine()); 
     string[] splitInput = inputLine.Split(); 
     EmpNum = int.Parse(splitInput[0]); 
     EmpName = (splitInput[1]); 
     EmpAdd = (splitInput[2]); 
     EmpWage = double.Parse(splitInput[3]); 
     EmpHours = double.Parse(splitInput[4]); 

     Console.WriteLine("test {0},{1},{2}", EmpNum, EmpWage, EmpHours); 

}

使用inputLine = (myFile.ReadLine());，然後進行分割操作從文件中第一次讀...

3）按照@Aaron Anodide的建議，插件GA檢查長度應該做的伎倆..

像..

inputLine = (myFile.ReadLine()); 
string[] splitInput = inputLine.Split(); 
if(splitInput!=null && splitInput.length ==5) 
{ 
EmpNum = int.Parse(splitInput[0]); 
     EmpName = (splitInput[1]); 
     EmpAdd = (splitInput[2]); 
     EmpWage = double.Parse(splitInput[3]); 
     EmpHours = double.Parse(splitInput[4]); 
     Console.WriteLine("test {0},{1},{2}", EmpNum, EmpWage, EmpHours); 
} 

Answer 4

添加一個破發點行拆分輸入後，那麼你可以鼠標所產生的陣列上，然後點擊加號。通過這種方式，您可以準確瞭解數據如何分割。如果有隱藏的字符會導致分割（\ n，\ t，\ r），這特別有用。

Answer 5

您有一行不包含足夠的項目。檢查數組的長度閱讀項目之前：

string[] splitInput = inputLine.Split(); 
if (splitInput.Length >= 5) { 
    EmpNum = int.Parse(splitInput[0]); 
    EmpName = (splitInput[1]); 
    EmpAdd = (splitInput[2]); 
    EmpWage = double.Parse(splitInput[3]); 
    EmpHours = double.Parse(splitInput[4]); 
} else { 
    // not enough items - show an error message or something 
} 

此外，正在檢查的變量input，而不是inputLine在where，但是這不是你的錯誤的原因。如果你讀到文件末尾，當試圖在分割中使用空引用時，你會得到一個空引用異常。

Answer 6

你有幾個問題。第一個問題是Split（）。您需要將inputLine.Split()更改爲inputLine.Split(',')。現在你調用System.String.Split(params char[])的重載，並且由於你沒有指定任何要分割的字符，它將返回整個字符串。

其他問題（作爲一個CS學生），你應該真正處理你的命名約定和錯誤檢查。代碼很脆弱，很容易中斷。您應該儘早開始學習良好的軟件工程實踐並編寫高質量的代碼。

using (FileStream fstream = new FileStream("path", FileMode.Open)) 
using (StreamReader reader = new StreamReader(fstream)) { 
    string line; 

    while (!reader.EndOfStream && (line = reader.ReadLine()) != null) { 
     string[] data = line.Split(','); 

     if (data.Length < 5) { 
      // You will have IndexOutOfRange issues 
      continue; // skip processing the current loop 
     } 

     int employeeNumber; 
     string employeeName; 
     string employeeAddress; 
     double employeeWage; 
     double employeeHours; 

     // Will be used to check validity of fields that require parsing into a type. 
     bool valid; 

     valid = int.TryParse(data[0], out employeeNumber); 

     if (!valid) { 
      // employee number is not parsable 
     } 

     employeeName = data[1]; 
     employeeAddress = data[2]; 

     valid = double.TryParse(data[3], out employeeWage); 

     if (!valid) { 
      // employee wage is not parsable 
     } 

     valid = double.TryParse(data[4], out employeeHours); 

     if (!valid) { 
      // employee hours are not parsable 
     } 
    } 
}