Regex正则替换字符

Question

将strOld中的数字1替换成A
strOld=1,2,1,13,112,11,1
替换后的结果：
strNew=A,2,A,13,112,11,A请问：
①在C#中用Regex.Replace该如何实现？
②在SQL中该如何实现？

Answer 1

            string strOld = "1,2,1,13,112,11,1";
            string strNew = Regex.Replace(strOld, @"(?<=,|^)1(?=,|$)", "A");

Answer 2

declare @str varchar(100)
set @str='1,2,1,13,112,11,1'
select left(stuff(replace(','+@str+',',',1,',',A,'),1,1,''),len(stuff(replace(','+@str+',',',1,',',A,'),1,1,''))-1)

Answer 3

                 string str = "1,2,1,13,112,11,1";            
str= Regex.Replace(str, @"\b1\b", "A");

Answer 4

这个其实不用正则：
str= (","+str+",").Replace(",1,",",A,").Trim(',');

Answer 5

++
string str="1,2,1,13,112,11,1";
str= (","+str+",").Replace(",1,",",A,").Trim(',');

Answer 6

试试这个字符串，替换后是什么结果strOld=1,1