| Title | 
                
                    Test
                    Find
                    
                    Password
                 | 
            
            
                | Expression | 
                ^([a-zA-Z0-9]{6,18}?)$  | 
            
            
                | Description | 
                My simple but effective password regex. The password can only contain letters and/or digits and must be at least 6 characters long and no more than 20. I know it says {6,18} but it just works out that way. The question mark was added for optimization. Also, the password can not begin or end with a space or underscore.  | 
            
            
                | Matches | 
                abc123  | 
            
            
                | Non-Matches | 
                _abc123_  | 
            
            
                | Author | 
                
                    Rating:
                        
 
                    tedcambron
                 | 
            
            
                | Source | 
                 | 
            
            
              | Your Rating | 
              
                
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	                Title: Can't contain other characters
	                Name: Ted Cambron
	                Date: 9/20/2014 7:26:00 PM
	                Comment: 
This pattern does limit just to letters and digits. #12343& or $10000! would not pass
                
                
            
                
	                Title: You Are Wrong
	                Name: blah
	                Date: 6/6/2009 10:04:42 AM
	                Comment: 
aaaa will match, that seems like 4 characters to me.
                
                
            
                
	                Title: Thank You
	                Name: Ted Cambron
	                Date: 2/22/2008 8:31:31 PM
	                Comment: 
Thanks for the advice. I think?
                
                
            
                
	                Title: Can contain other characters
	                Name: Michael Ash
	                Date: 2/22/2008 1:25:27 PM
	                Comment: 
This pattern does not limit just to letters and digits.
#12343& or $10000! would pass