正则表达式积累

验证数字：
只能输入1个数字 

 
表达式 ^\d$ 
描述 匹配一个数字 
匹配的例子 0,1,2,3 
不匹配的例子  


只能输入n个数字 

 

Regular Expressions (1) ---- What is Regular Expressions? 
Regular Expressions (2) ---- Common Used Samples
Regular Expressions (3) ---- Using Regex in .NET