I bag your pardon but I'm in need of any help. I must check String instance in C#. The String must contains only uppercase and lowercase English letters and '|' characters. How can I do this checking with Regex class in .NET Framework 4.5.? Suppose I got the String from Console:
String _processedString = Console.ReadLine(); How can I check it to according to above mentioned conditions?
Use a regular expression:
var regex = new Regex("^[A-Z|]+$"); Console.WriteLine(regex.IsMatch("HELLO|THERE")); // True Console.WriteLine(regex.IsMatch("Hello")); // False Console.WriteLine(regex.IsMatch("HI THERE")); // False Console.WriteLine(regex.IsMatch("HEÎ")); // False Explanation:
^ matches beginning of line
[ starts one-of-these-characters matching
A-Z matches uppercase English letters
| matches the | character, but if it was outside the [ ] characters it would need to be escaped, normally | is the or operator.
] ends the one-of-these-characters matching
+ means "one or more"
$ means end of line
^[a-zA-Z|]+$to validate your input.