字符串学习总结

1. //判断字符串是否包含“|”       string aaa="123";       if (aaa.Contains("|") == true)       { Response.Write("you"); }       else       { Response.Write("meiyou"); }2.  //删除重复字符串        string st = "1,2,3,23,3,24,34,23,3";        string[] stArr = st.Split(',');        ArrayList al = new ArrayList();        foreach (string qq in stArr)        {            if (!al.Contains(qq))                al.Add(qq);        }        st = "";        for (int i = 0; i < al.Count; i++)        {            st += al[i] + ",";        }        st = st.Substring(0, st.Length - 1);        Response.Write(st);3. //剪取字符串        string[] str = new string[5]              {"张晓梅的好友/注册时间为/09-08-04 10:40:2/已注册 ",               "张晓梅的好友/注册时间为/09-08-05 3:30:10/已注册 ",               "张晓梅的好友/注册时间为/09-08-06 12:32:14/已注册 ",               "张晓梅的好友/注册时间为/09-08-07 9:58:52/已注册 ",               "张晓梅的好友/注册时间为/09-08-08 10:40:30/已注册"              };        foreach (string a in str)        {            string[] cc = a.Split('/');            Response.Write(cc[2] + "<br/>");        }4. //日期变化，设定固定时间        DateTime now = System.DateTime.Now;        string aa = now.ToString();        string dd=aa.Remove(10);        string bb = aa.Replace(aa,dd+"08:00:00");        DateTime ee = Convert.ToDateTime(bb);              Response.Write(ee);5.//判断是否存在星期六，星期天        DateTime aa =Convert.ToDateTime( "2009-09-01");        DateTime bb =Convert.ToDateTime( "2009-09-07");        for (DateTime dt = aa; dt <= bb; dt = dt.AddDays(1))        {            if (dt.DayOfWeek == DayOfWeek.Saturday || dt.DayOfWeek == DayOfWeek.Sunday)            { Response.Write("Exist"); }        }