C#從零開始_自學C#、Visual Studio實境秀 35/ 漢字資訊處理 如何避免字串長度誤判

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5:30 Because a single character can be represented by multiple Char objects, it is not always meaningful to work with individual Char objects.

7:10 維基怎麼固定使用繁體台灣的介面設定

21:00 Characters and text elements

14:50 如何避免字串長度誤判；You can do the following to avoid the assumption that a Char object represents a single character. http://bit.ly/2t46QXH

Char.ConvertFromUtf32()  .Length 計算出問題！

23:00 漢字資訊處理

You can work with a String object in its entirety instead of working with its individual characters to represent and analyze linguistic content.

You can use the StringInfo class to work with text elements instead of individual Char objects. The following example uses the StringInfo object to count the number of text elements in a string that consists of the Aegean numbers zero through nine. Because it considers a surrogate pair a single character, it correctly reports that the string contains ten characters.

1:08:00 System.String.Normalize method

1:13:40 字串 string 其實就是一個 char 的集合或陣列 Convert.ToUInt16(s[ctr])

using System;



public class Example

{

  public static void Main()

  {

 string combining = "\u0061\u0308";

 ShowString(combining);



 string normalized = combining.Normalize();

 ShowString(normalized);

  }



  private static void ShowString(string s)

  {

 Console.Write("Length of string: {0} (", s.Length);

 for (int ctr = 0; ctr < s.Length; ctr++) {

Console.Write("U+{0:X4}", Convert.ToUInt16(s[ctr]));

if (ctr != s.Length - 1) Console.Write(" ");

 }

 Console.WriteLine(")\n");

  }

}

// The example displays the following output:

//       Length of string: 2 (U+0061 U+0308)

//      

//       Length of string: 1 (U+00E4)

1:25:30 用中文測試以上方式無效，可見 Normalize 只對  a string contains a base character that has one or more combining characters 有效

2:00:30 char (C# Reference)

char[] chars = new char[4];



chars[0] = 'X';        // Character literal

chars[1] = '\x0058';   // Hexadecimal

chars[2] = (char)88;   // Cast from integral type

chars[3] = '\u0058';   // Unicode



foreach (char c in chars)

{

Console.Write(c + " ");

}

// Output: X X X X







逐步解說：使用類別庫建立 Web 應用程式專案

{ 類別庫

http://bit.ly/2ugpIqh http://bit.ly/2gOYSB3

建構函式的存取層級會判斷哪些用戶端可以建立類別的執行個體。

在 C# 中將 using 陳述式 (在 Visual Basic 中為 Imports 陳述式)

}



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