CODEWITHSUNDEEP
c#
Kristian Kostov
Kristian Kostov

Reputation: 3

How to check if there is a character between two spaces C#

I have a string and want to check if there is a letter(only one) that is surrounded by spaces. I tried using Regex but something is not right.

Console.Write("Write a string: ");
string s = Console.ReadLine();
string[] results = Regex.Matches(s, @" (a-zA-Z) ")
.Cast<Match>()
.Select(m => m.Groups[1].Value)
.ToArray();

I am not sure if I am doing this right I am new to C#

Upvotes: 0

Views: 316

Answers (1)

nvoigt
nvoigt

Reputation: 77294

A full blown RegEx seems to be heavy stuff for such a simple operation.

This is a sample how to do it. It does include a lot of assumptions that might not be true for you (the fact that I don't consider start or end of string a valid whitespace, the fact I check for WhiteSpace instead of blank, you will have to check those assumptions I made). 

namespace ConsoleApplication4
{
  using System;
  using System.Collections.Generic;
  using System.Linq;

  public static class StringExtensions
  {
    public static IEnumerable<int> IndexOfSingleLetterBetweenWhiteSpace(this string text)
    {
      return Enumerable.Range(1, text.Length-2)
                       .Where(index => char.IsLetter(text[index]) 
                                    && char.IsWhiteSpace(text[index + 1])
                                    && char.IsWhiteSpace(text[index - 1]));
    }  
  }

  class Program
  {
    static void Main()
    {
      var text = "This is a test";

      var index = text.IndexOfSingleLetterBetweenWhiteSpace().Single();

      Console.WriteLine("There is a single letter '{0}' at index {1}", text[index], index);
      Console.ReadLine();
    }
  }
}

This should print

There is a single letter 'a' at index 8

Upvotes: 3

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