轻松学习C#的String类

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
  static void Main(string[] args) 
  { 
   string nums = "0123456789"; 
   string newnums1; 
   string newnums2; 
   newnums1 = nums.Substring(5);//截取从索引5开始后的字符 
   newnums2 = nums.Substring(3,5);//截取从索引3开始数5个字符 
   Console.WriteLine(newnums1); 
   Console.WriteLine(newnums2); 
   Console.ReadLine(); 
  } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
  static void Main(string[] args) 
  { 
   string str="abcefgaabsbdeesdabc"; 
   Console.WriteLine("原字符串为{0}",str); 
   Console.WriteLine("通过单个字符e分割后如下："); 
   string[] singleSplit = str.Split('e');//进行单个字符分割的方法 
   foreach (string outstr in singleSplit) 
   { 
    Console.WriteLine(outstr); 
   } 
   Console.WriteLine("通过多个字符e,b,s分割后如下："); 
   string[] multiSplit = str.Split(new char[] {'e','b','s'});//进行多个字符分割的方法 
   foreach (string outstr in multiSplit) 
   { 
    Console.WriteLine(outstr); 
   } 
   Console.ReadLine(); 
  } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
  static void Main(string[] args) 
  { 
   string str1 = "abc"; 
   string str2 = "ghj"; 
   string[] array = {"123","456","789"}; 
   string str3 = str1 + str2; 
   string str4 = string.Concat(str1,str2); 
   string str5 = string.Join("|",array);//将数组中元素合并为一个新的字符串 
   Console.WriteLine(str3); 
   Console.WriteLine(str4); 
   Console.WriteLine(str5); 
   Console.ReadLine(); 
  } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
  static void Main(string[] args) 
  { 
   string str = "abcadfaslfj"; 
   string replacestr = str.Replace("a","|");//用“|”替换“a” 
   Console.WriteLine(replacestr); 
   Console.ReadLine(); 
  } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
  static void Main(string[] args) 
  { 
   string str = "abcdefg"; 
   string insertstr; 
   string padrightstr; 
   string padleftstr; 
   insertstr = str.Insert(5,"12345"); 
   padrightstr = str.PadRight(10,'v'); 
   padleftstr = str.PadLeft(10,'w'); 
   Console.WriteLine(insertstr); 
   Console.WriteLine(padrightstr); 
   Console.WriteLine(padleftstr); 
   Console.ReadLine(); 
  } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
 static void Main(string[] args) 
 { 
  string str = "0123456789"; 
  string delstr1; 
  string delstr2; 
  delstr1 = str.Remove(6);//删除字符串索引为6后面的字符 
  delstr2 = str.Remove(5,5);//删除字符串索引自5开始后数5个长度的字符 
  Console.WriteLine(delstr1); 
  Console.WriteLine(delstr2); 
  Console.ReadLine(); 
 } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
 static void Main(string[] args) 
 { 
  string str = "This is a string"; 
  string copystr; 
  copystr = string.Copy(str); 
  char[] newchar=new char[20]; 
  str.CopyTo(5,newchar,0,11); 
  Console.WriteLine(copystr); 
  Console.WriteLine(newchar); 
  Console.ReadLine(); 
 } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
 static void Main(string[] args) 
 { 
  string str = "This is a string"; 
  string lowerstr; 
  string upperstr; 
  lowerstr = str.ToLower(); 
  upperstr = str.ToUpper(); 
  Console.WriteLine("小写形式：{0}",lowerstr); 
  Console.WriteLine("大写形式：{0}",upperstr); 
  Console.ReadLine(); 
 } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
 static void Main(string[] args) 
 { 
  string str = "This is a string"; 
  int rh1 = str.IndexOf("i"); 
  int rh2 = str.LastIndexOf("i"); 
  if (rh1>=0) 
  { 
  Console.WriteLine("字符i在字符串str第一次出现的位置是：{0}",rh1); 
  Console.WriteLine("字符i在字符串str最后一次出现的位置是：{0}", rh2); 
  } 
  else 
  { 
  Console.WriteLine("字符i在字符串str未出现"); 
  } 
  Console.ReadLine(); 
 } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
 static void Main(string[] args) 
 { 
  StringBuilder str =new StringBuilder( "Hellow World!"); 
  Console.WriteLine("---Append---"); 
  str.Append("What a beautiful day"); 
  Console.WriteLine("追加后的字符串为：{0}",str); 
  Console.ReadLine(); 
 } 
 } 
}

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 
 
namespace 字符串 
{ 
 class Program 
 { 
 static void Main(string[] args) 
 { 
  Console.WriteLine(@"C:\Windows\system32");//第一种输出格式就是在前面加@ 
  Console.WriteLine("C:\\Windows\\system32");//第二种输出格式就是将"\"改成"\\" 
  Console.ReadLine(); 
 } 
 } 
}