检索文本文件中的特定数据（visual basic .NET） [英] Retrieve specific data in a text file (visual basic .NET)

问题描述

嗨！我一直有这个问题，而我似乎无法找到办法。我希望你能提供帮助。



所以，假设有一个名为的文本文件：



Games.txt

使命召唤：50

Assasins信条：23

看门狗：140



我的问题是，如果我想知道Assasins Creed的数量我该怎么做？



i希望论坛上有人我知道如何做到这一点，感谢你提前帮助。



我尝试过：



我试过通过知道字符串的长度来找到它。然后读取并删除前15个字符（

Assasins Creed：

）这将留下我：23.但这是一个非常糟糕的做法，而且我总是要知道确切的线。更好的解决方案是

解决方案

它并不复杂，有几种方法可以做到。

您可以将文件读取为系列行，并找到以Assassins Creed：开头的行（string.StartsWith将告诉你）。剩下的就是你的号码。



您可以将整个文件读作一个字符串（File.ReadAllText会这样做），然后使用正则表达式查找你想要的数据：

 私人 静态 Regex findIt =  new 正则表达式（
   （？< = Assasins Creed：\\\\ +）\\\\ +，
 RegexOptions.Multiline 
 | RegexOptions.CultureInvariant 
 | RegexOptions.Compiled 
）; 
 ... 
匹配m = findIt.Match（textFromTheFile）; 
  if （m.Success）
 {
  string  theValueYouWanted = m.Value; 
 ... 
} 

无论如何，一旦有了数据，就可以使用int.TryParse将其转换为数字：

< pre lang =c＃> int assassinsCreedCount;
if （ int .TryParse（theValueYouWanted， out assassinsCreedCount））
{
// 你知道了。
...
}

这个伪代码，你可能需要调整语法

1.打开File into streamreader

2.逐行循环

3.检查值并显示

  Dim  FILE_NAME 作为 字符串 =   C：\ Users \Owner \Documents\Games.txt 
 如果 System.IO.File.Exists（FILE_NAME）=  True  然后 
  Dim  objReader  As  新 System.IO.StreamReader（FILE_NAME）
 
  Dim  TextLine 作为 字符串 
  Dim  LineArray（）作为 字符串 
  Dim  LineKey 作为 字符串 
  Dim  LineValue  As   String  
 
     objReader.Peek（）<> -1 
 TextLine = objReader.ReadLine（）
 LineArray = TextLine.Split（' ：' ） 
 LineKey = LineArray（ 0 ）
 LineValue = LineArray（ 1 ）
 ' 如果LineKey =Assasins Creed，则LineValue将等于所需金额 
 循环 
 结束 

Hi! Ive been having this issue, And i just cant seem to find a way to do it. I hope you can help.

So, lets say a have a text file called:

"Games.txt"
Call of Duty: 50
Assasins Creed: 23
Watch Dogs: 140

My question is, If i wanted to know the number of "Assasins Creed" How would i do it?

i hope someones on the forum knows how to do this, Thanks for you help in advance.

What I have tried:

I have tried finding it by knowing the line, length of the string. Then reading that and removing the first 15 charachters (

"Assasins Creed:"

) That would leave me with: 23. But this is a pretty bad way of doing it, And i always have to know the exact line. A better sollution would be

解决方案

It's not complex, there are several ways you could do it.
You could read the file as a series of lines, and find the line starting with "Assassins Creed:" (string.StartsWith will tell you that). The rest of the line is your number.

You could read the whole file as a string (File.ReadAllText will do that) and then use a Regular Expression to find the data you want:

private static Regex findIt = new Regex(
      "(?<=Assasins Creed:\\s+)\\d+",
    RegexOptions.Multiline
    | RegexOptions.CultureInvariant
    | RegexOptions.Compiled
    );
...
    Match m = findIt.Match(textFromTheFile);
    if (m.Success)
        { 
        string theValueYouWanted = m.Value;
        ...
        }

Wither way, once you have the data, you can use int.TryParse to convert it to a number:

int assassinsCreedCount;
if (int.TryParse(theValueYouWanted, out assassinsCreedCount))
   {
   // You got it.
   ...
   }

This pseudo-code, you may need to adjust syntax
1. Open File into streamreader
2. Loop through line by line
3. Check value and display

Dim FILE_NAME As String = "C:\Users\Owner\Documents\Games.txt"
If System.IO.File.Exists(FILE_NAME) = True Then
  Dim objReader As New System.IO.StreamReader(FILE_NAME)

  Dim TextLine As String
  Dim LineArray() As String
  Dim LineKey As String
  Dim LineValue As String

  Do While objReader.Peek() <> -1
    TextLine = objReader.ReadLine()
    LineArray = TextLine.Split(':')
    LineKey = LineArray(0)
    LineValue = LineArray(1)
    ' if LineKey = "Assasins Creed" then LineValue will equal the desired amount
  Loop
End

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