C# 截取字符串基本

            #region --构建字符串处理
            string str1 = "123AAA456AAAA789AAAAAAA1011";
            string str2 = "123456789AAA23456789AAAA3456789AAAAAAA4567890";
            string str3 = "123456788AAA23456789AAAA3456789AAAAAAA4567890";
            string str4 = "123456788AAA0AAAA0AAAAAAA";
            var strArry = (str1 + "&" + str2 + "&" + str3 + "&" + str4).Split('&'); //把字符串连接为数组

            for (int i = 0; i < strArry.Length; i++)
            {
                var serachstr1 = "AAA";
                var serachstr2 = "AAAA";
                var serachstr3 = "AAAAAAA";

                //查找3个A所在位置
                int index1 = strArry[i].IndexOf(serachstr1);
                //查找4个A所在位置
                var index2 = strArry[i].IndexOf(serachstr2, index1 + serachstr1.Length);
                //查找7个A所在位置
                var index3 = strArry[i].IndexOf(serachstr3, index2 + serachstr2.Length);

                //截取字符串
                var result1 = strArry[i].Substring(0,index1);
                var result2 = strArry[i].Substring(index1 + serachstr1.Length, index2- (index1 + serachstr1.Length));
                var result3 = strArry[i].Substring(index2 + serachstr2.Length, index3-(index2 + serachstr2.Length));
                var result4 = strArry[i].Substring(index3 + serachstr3.Length);
            }
            #endregion

 C# 统计字符串出现的次数

            string str1 = "123AAA456AAAA789AAAAAAA1011";
            char[] str1Arry = str1.ToArray();
            int js = 0;
            List<int> TempArry = new List<int>();
            for (int i=0;i< str1Arry.Length;i++)
            {
                if (str1Arry[i]=='A')
                {
                    js++;
                    continue;
                }
                if (js!=0) //找到A, 不等于A时候执行
                {
                    TempArry.Add(js);
                    js = 0; //js归0
                }
            }