C# regex exact length

Question

I have a program, that has to output substrings of exact length using regexp. But it outputs also substrings of a greater length, which match format. input: a as asb, asd asdf asdfg expected output(with length = 3): asb asd real output: asb asd asd asd ``` using System; using System.Collections.Generic; using System.Linq; using System.Text.RegularExpressions; namespace LR3_2 { class Program { static void regPrint(String input, int count) { String regFormat = @"[a-zA-Z]{" + count.ToString() + "}"; Regex reg = new Regex(regFormat); foreach (var regexMatch in reg.Matches(input)) { Console.Write(regexMatch + " "); } //Match matchObj = reg.Match(input); //while (matchObj.Success) //{ // Console.Write(matchObj.Value + " "); // matchObj = reg.Match(input, matchObj.Index + 1); //} } static void Main(string[] args) { String input = " "; //Console.WriteLine("Enter string:"); //input = Console.ReadLine(); //Console.WriteLine("Enter count:"); //int count = Console.Read(); input += "a as asb, asd…

Accepted Answer

Add `\b`, which means "at beginning or end of a word", to your expression, for example:

```
\b[a-zA-Z]{3}\b
```

In your code you should do the following:

```
String regFormat = @"\b[a-zA-Z]{" + count.ToString() + @"}\b";
```

To test regular expression before coding your own test program, you can use tools like Expresso or The Regulator. They actually help you writing the expression and test it.

C# regex exact length

Solution

Problem