C# 字符串处理小节
//两种字符串比较
/* string str1 = "apple";
string str2 = "apple";
long t1 = System.DateTime.Now.Ticks;
for (long i = 0; i < 10000000; i++)
{ if (str1 == str2) { } }
long t2 = System.DateTime.Now.Ticks;
for (long i = 0; i < 10000000; i++)
{ if (str1.Equals(str2)) { } }
long t3 = System.DateTime.Now.Ticks;
Console.WriteLine("str1==str2方法用时:" + (t2 - t1) + "str1.Equals(str2)方法的用时:" + (t3 - t2));
Console.ReadKey();*/
//C#字符串模糊比较问题：
/* string num1 = "123456";
string num2 = "123432;123456;334532;33565464";
if (num2.Contains(num1))
{
Console.WriteLine("num2 包含num1");
}
else
{
Console.WriteLine("false");
}
Console.ReadKey();*/
// indexOf()方法进行判断
/* string num1 = "123456";
string num2 = "123432;123456;334532;33565464";
if (num2.IndexOf(num1) >-1)
{
Console.WriteLine("num2 包含num1");
}
Console.ReadKey();*/
//字符串定位问题//1
/*string str1 = "窗内网#http//www.itzcn.com*";
int a= str1.IndexOf('*');
int b = str1.IndexOf('#');
string getstr = string.Empty;
int[] c = new int[] {a,b };
Array.Sort(c);
foreach (int i in c)
{
if (a==i)
{
getstr = "*";
break;
}
else
{
getstr = "#";
break;
}
}
Console.WriteLine(getstr);
Console.ReadKey();*/
//2
/*string str1 = "大家好";
string str2 = "好";
if(str1.EndsWith(str2))
{
Console.WriteLine("字符串str1末尾与字符串str2相等");
}
Console.ReadKey();*/
//检索字符串中的某个字符出现的次数
/* string str = "hello,please come to my office the afernoon";
string s = "o";
int start = 0;
int count = 0;
while (start != -1)
{
start = str.IndexOf(s,start);
if (start != -1)
{
count++;
start++;
}
}
Console.WriteLine(count.ToString());
Console.WriteLine(start.ToString());
Console.WriteLine(str.Length);
Console.ReadKey();*/
//去掉字符串中指定的子字符串的问题
/* string s = "<img a></br>123456<img a></br><img a></br>asdddss";
s = s.Replace("</br>","$");
int start = 0;
while(start!=-1)
{
start = s.IndexOf("<img");//获取<img的起始索引
//Console.WriteLine(start);0,6,6,-1
if (start != -1)
{
int startindex = s.IndexOf("<img");
int endindex = s.IndexOf("$", startindex);
//Console.WriteLine(endindex);//7,13,13
s = s.Remove(startindex, endindex - startindex + 1);
}//删除指定的字符串元素
}
s = s.Replace("$","</br>");
Console.WriteLine(s);
Console.ReadKey();*/
//C#截取字符串
/* string str = "2013-10-1 10:10:10*456*654*2013-10-2";
int index1 = str.IndexOf("*");
string str1 = str.Substring(0,index1);
int index3 = str.LastIndexOf("*");
string str3 = str.Substring(index3+1);
int index2 = index1 + 1;
string str2 = str.Substring(index2,index3-index2);
Console.WriteLine(str1);
Console.WriteLine(str3);
Console.WriteLine(str2);
Console.ReadKey();*/
//截取长度为8的字符串
/* string str = "从数据库中截取的新闻标题练习题";
string str1 = "";
if (str.Length > 8)
{
str1 = str.Substring(0, 8);
}
else
{
str1 = str;
}
Console.WriteLine(str1);
Console.ReadKey();*/
//截取第一个s和第一个n之间的字符串
/* string str = "ennnnnglisssssh";
string stn = str.Substring(str.IndexOf("n")+1,str.IndexOf("s")-str.IndexOf("n"));
Console.WriteLine(stn);
Console.ReadKey();*/
//分割存储用户信息的字符串
/* string userinfo = "userid=1&username=admin&password=admin123";
char[] charList = {'&','=' };
string[] userlist = userinfo.Split(charList);
Console.WriteLine("用户编号:{0}",userlist[1]);
Console.WriteLine("用户名:{0}",userlist[3]);
Console.WriteLine("用户密码:{0}",userlist[5]);
Console.ReadKey();*/
//把字符串中不同字符分开的数据取出来
/*string mystring = "12323443,344533;34556654 45564345";
char[] char_list = new char[] {',',';',' ' };
string[] mystr = mystring.Split(char_list);
foreach(string str in mystr)
{
if(str!="")
{
Console.WriteLine(str);
}
}
Console.ReadKey();*/
//
//不考虑大小写的方法
/* string str = "123asd";
string str1 ="123AAAsd";
if (string.Compare(str, str1, true) > 0)
{
Console.WriteLine("two eques is true");
}
else if (string.Compare(str, str1, true) < 0)
{
Console.WriteLine("str<str1");
}
else
{
Console.WriteLine("str>str1");
}
Console.ReadKey();*/
//string and stringbuilder的执行效率哪个更高
//StringBuilder的执行效率高
//
//Format格式化
// 正则表达式问题
