C#：对字符串的各种处理

字符串截取

SubString OR Remove

  string str3 = "123abc456";

  //str3 = str3.Substring(0, i);  //从左边开始取字符串的前i个字符(str3 = str3.Remove(i, str3.Length - i);)
  str3 = str3.Substring(, );
  str3 = str3.Remove(, str3.Length - );
  //输出："123"

  //str3 = str3.Substring(i);     //从左边开始去掉字符串的前i个字符(str3=str3.Remove(0,i);)
  str3 = str3.Substring();
  //输出："abc456"
  //str3 = str3.Substring(str3.Length - i);  //从右边开始取i个字符(str3=str3.Remove(0,str3.Length-i))
  str3 = str3.Substring(str3.Length - );
  //输出："456"

  //str3 = str3.Substring(0, str3.Length - i); //从右边开始去掉i个字符(str3=str3.Remove(str3.Length-i,i))
  str3 = str3.Substring(, str3.Length - );
  //输出："123abc"

Trim

   string str = " I Believe You Very Much! ";
   str = str.TrimStart();                                  //截取掉字符串首部的空格
   //输出："I Believe You Very Much! "

   str = str.TrimStart('I');                               //截取掉字符串第一个字符
   //输出："Believe You Very Much! "

   str = str.TrimStart().TrimStart("Beli".ToCharArray());  //截取掉字符串首部及尾部出现的B或e或l或i字符,删除的过程直到碰到一个既不是B也不是e也不是l也不是i的字符才结束。
   //输出："ve You Very Much! "

   string str1 = " I Believe You Very Much! ";
   str = str1.Trim();                                      //截取掉字符串首部和尾部的空格
   //输出："I Believe You Very Much!"

   //TrimEnd的方法和TrimStart原理一样不多赘述
   string str2 = " I Believe You Very Much! ";
   str = str2.TrimEnd();                                   //截取掉字符串首部和尾部的空格
   //输出：" I Believe You Very Much!"

字符串替换

Replace

   string str5 = "123abc456efg";
   str5 = str5.Replace("efg", "EFG");
   //输出："123abc456EFG"

字符串分割

Split

    string str6 = "123,abc,456,efg";
    string[] str6s = str6.Split(',');
    foreach (var item in str6s)
    {
          ConsoleStr(item);
    }
    //输出："123 abc 789 efg"

字符串连接

Join

 //结合split里面的字符串数组str6s
 string str7 = string.Join("-", str6s);
 //输出："123-abc-456-efg"

字符串转换大小写

  string str8 = "abcdefgHIJK";
  str8 = str8.ToUpper();
  //输出："ABCDEFGHIJK"

  str8 = str8.ToLower();
  //输出："abcdefghijk"

  bool isUpper = char.IsUpper(str8, );
  //输出："True"

字符串比较

   string str10 = "abackhdk";

   string str9 = "abac";
   int aa = str9.CompareTo(str10);
    //输出："-1"

   string str11 = "b";
   int bb = str11.CompareTo(str10);
   //输出："1"

   string str12 = "abackhdk";
   int cc = str12.CompareTo(str10);
   //输出："0"

查找子串

 str.IndexOf(子串，查找其实位置) ;
 str.LastIndexOf(子串) ;最后一次出现的位置
 str.IndexOf("ab",);

插入子串

 str.Insert(插入位置，插入子串) ;
 s.Insert(,"ab");

移出子串

这里Remove我已经和Substring一起说了。就不细说了

 str.Remove（其实位置，移出数）;
 s.Remove(,);