c#中字符串的常用函数

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace Str

{

class Program

{

static void Main(string[] args)

{

string str1 = "aBc";

char[] chrs = str1.ToCharArray();//把string转化为char[]

foreach(char chr in chrs)

{

Console.WriteLine(chr);

}

str1 = str1.ToLower();//返回string类型，把字符串变为小写

Console.WriteLine(str1);

str1 = str1.ToUpper();//返回string类型，把字符串变为大写

Console.WriteLine(str1);

bool b = str1.Equals("ABC", StringComparison.OrdinalIgnoreCase);//忽略大小写比较

Console.WriteLine(b);

string str2 = " what a good day! ";

str2 = str2.Trim();//去掉字符串两边的红白，中间的空白不去除

Console.WriteLine(str2);

string str3 = "aa,b|c,ff.h";

string[] str4 = str3.Split(',', '|', '.');

foreach(string item1 in str4)

{

Console.WriteLine(item1);

}

string str5 = ",,c,,b,c,,,,c";

string[] str6 = str5.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);

foreach (string item2 in str6)

{

Console.WriteLine(item2);

}

string str7 = "我是狗我是猫我是王八蛋";

string[] str8 = str7.Split(new string[] { "我是" }, StringSplitOptions.RemoveEmptyEntries);

foreach(string item3 in str8)

{

Console.WriteLine(item3);

}

str7 = str7.Replace("我是", "你是");//原型string Replace(string oldString, string newString);//用新串替换旧窜

Console.WriteLine(str7);

str7 = str7.Substring(6);//得到从某个位置开始至字符串末尾的子串

Console.WriteLine(str7);

str7 = str7.Substring(0, 2);//得到从某个位置开始并且长度为length的子串

Console.WriteLine(str7);

string str9 = "what a good day! Let's party,goodbye";

bool b1 = str9.Contains("what");//判断串中是否含有某个串

Console.WriteLine(b1);

bool b2 = str9.StartsWith("where");//判断串是否是以某个串开始

Console.WriteLine(b2);

bool b3 = str9.EndsWith("bye");//判断串是否是以某个串结束

Console.WriteLine(b3);

int ipos = str9.IndexOf("day");//某个串第一次出现的位置

Console.WriteLine(ipos);

Console.ReadKey();

}

}

}