求个字符串函数

Question

要求将一个字符串的1、2位字符颠倒，3、4位字符颠倒，5、6位字符颠倒，7、8位字符颠倒，9、100位字符颠倒，按照这样的规律将字符串的每2位字符做颠倒，例如下面的字符串1234567890
2143658709
------------------
1234567890ABCDEFG
2143658709BADCFEG
------------------
2143658709BADCFEG
1234567890ABCDEFG

Answer 1

streamreader读取每一行，自己判断奇偶数，然后互换，最后在写回去

Answer 2

        private string ProcessString(string s)
        {
            StringBuilder Builder = new StringBuilder("");
            for (int n = 0; n < s.Length; n++)
            {
                if (n % 2 == 0) Builder.Append(s[n]);
                else Builder.Insert(Builder.Length - 1, s[n]);
            }
            return Builder.ToString();
        }

Answer 3

  public string Dee(string str)
        {
            string a = str;
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i <= a.Length - 1; i++)
            {
                if (i + 1 != a.Length)
                {
                    sb.Append(a[i + 1]);
                    sb.Append(a[i]);
                    i = i + 1;
                }
                else
                {                }
                {
                    sb.Append(a[i]);
                }
            }
            return sb.ToString();
        }

Answer 4

public string Dee(string str)
        {
            string a = str;
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i <= a.Length - 1; i++)
            {
                if (i + 1 != a.Length)
                {
                    sb.Append(a[i + 1]);
                    sb.Append(a[i]);
                    i = i + 1;
                }
                else
                {
                    sb.Append(a[i]);
                }
                
            }
            return sb.ToString();
        }
这个才是..上面那个多了个大括号..这复制.....

Answer 5

void Main()
{
var list=new List<string>{"1234567890","1234567890ABCDEFG","2143658709BADCFEG"};
list.ForEach(l=>
{  
Console.WriteLine("{0} \t {1}",l,string.Join("",Regex.Split(l,"(?<=\\G\\d{2})").Select(x=>new string(x.ToCharArray().Reverse().ToArray())).ToArray()));
});
 /*
1234567890   2143658709
1234567890ABCDEFG   2143658709GFEDCBA
2143658709BADCFEG   1234567890GEFCDAB  */
}

Answer 6

封装起来：
void Main()
{
var list=new List<string>{"1234567890","1234567890ABCDEFG","2143658709BADCFEG"};
list.ForEach(l=>
{  
Console.WriteLine("{0} \t {1}",l,ReverseString(l));
});
 /*
1234567890   2143658709
1234567890ABCDEFG   2143658709GFEDCBA
2143658709BADCFEG   1234567890GEFCDAB  */
}
string ReverseString(string str)
{
   return string.Join("",Regex.Split(str,"(?<=\\G\\d{2})").Select(x=>new string(x.ToCharArray().Reverse().ToArray())).ToArray());
}

Answer 7

string ReverseString(string str)
{
   return string.Join("",Regex.Split(str,"(?<=\\G.{2})").Select(x=>new string(x.ToCharArray().Reverse().ToArray())).ToArray());
}注意修改一下正则，保证能处理所有字符串

Answer 8

正则不需求那么麻烦啊
Regex reg = new Regex(@"(.)(.)");
string result = reg.Replace(yourStr, "$2$1");