How can I check if a string contains only English uppercase and lovercase letters and '|' characters?

Question

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?

You can use this regex: `^[a-zA-Z|]+$` to validate your input. — anubhava, May 18 '14 at 15:35
Why do you believe in restrictions? Allow the user to enter anything! — devnull, May 18 '14 at 15:35
This question can be filed in the category of "I don't even want to bother trying so let's see if the internet will just tell me the answer". — siride, May 18 '14 at 15:48

score 0 · Answer 1 · answered May 18 '14 at 15:41

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

How can I check if a string contains only English uppercase and lovercase letters and '|' characters?

1 Answers1