Some string extension methods for C# 3.0

StringHelpers.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace GitHub.Gist {
    /// <summary>
    /// Extension methods for working with strings
    /// </summary>
    public static class StringHelpers {
        
        /// <summary>
        /// Allow us to do <c>foo.IsNullOrEmpty()</c> rather than the slightly
        /// more verbose <c>string.IsNullOrEmpty(foo)</c>
        public static bool IsNullOrEmpty(this string s) {
            return string.IsNullOrEmpty(s);
        }
        
        /// <summary>
        /// Replaces all spaces in <c>s</c> with the hyphen "-"
        /// </summary>
        /// <param name="s">The s.</param>
        /// <returns></returns>
        public static string Hyphenate(this string s) {
            return Regex.Replace(s, @"(\s+|%20|\+)", "-");
        }

        /// <summary>
        /// Unhyphenates the specified string <c>s</c> by replacing all hyphens
        /// with a single space.
        /// </summary>
        /// <param name="s">The s.</param>
        /// <returns></returns>
        public static string Unhyphenate(this string s) {
            return Regex.Replace(s, @"-", " ");
        }

        /// <summary>
        /// Capitalises the first letter of each word in <c>s</c>.
        /// </summary>
        /// <param name="s">The s.</param>
        /// <returns></returns>
        public static string Capitalise(this string s) {
            return Regex.Replace(s, @"\b[a-z]", m => m.Value.ToUpper());
        }
        
        // Regex methods so we can operate directly on string objects, rather
        // than using the static Regex class methods
		
	public static bool IsMatch(this string s, string pattern) {
		return Regex.IsMatch(s, pattern);
	}
	
	public static string[] Split(this string s, string pattern) {
		return Regex.Split(s, pattern);
	}
	
	public static Match Match(this string s, string pattern) {
		return Regex.Match(s, pattern);
	}
	
	public static MatchCollection Matches(this string s, string pattern) {
		return Regex.Matches(s, pattern);
	}

        public static bool IsInt32(this string s) {
            int tmp;
            if (Int32.TryParse(s, out tmp)) {
                return true;
            }

            return false;
        }

        public static bool IsNotInt32(this string s) {
            return !IsInt32(s);
        }

    }
}