gistfile1.cs

string keyPad = @"2 = ABC2
	3 = DEF3
	4 = GHI4
	5 = JKL5
	6 = MNO6
	7 = PQRS7
	8 = TUV8
	9 = WXYZ9";
	Dictionary<char,char> keyMap = new Dictionary<char,char>();
	//4663 can lead to "good","home" etc
	string key = "4663";
	//"735328";//select/reject
	//"select" and "reject" can be typed using the key combination "735328"
	List<KeyValuePair<string,string>> keyAndLetters =
	keyPad.ToLower()
	.Split(new char[]{'\r','\n'},StringSplitOptions.RemoveEmptyEntries)
	.Select
	(
	p  => 
		new KeyValuePair<string,string>(p.Split('=')[0].Trim(),p.Split('=')[1].Trim()))
	.ToList();
	foreach (var keyL in keyAndLetters)
	{
	foreach (char c in keyL.Value.ToCharArray())
	keyMap.Add(c,Convert.ToChar( keyL.Key));
	}
	StreamReader sr = new StreamReader ("C:\\T9.txt");
	string total = sr.ReadToEnd();
	sr.Close();
	var query = total
				.Split(new char[]{'\r','\n',' '},StringSplitOptions.RemoveEmptyEntries)
				.Where (t  =>  t.Length==key.Length)
				.Select (t  =>  t.Trim());
	query
			.ToList()
			.Select(w =>  new KeyValuePair<string,string>(w,
				new string( w.ToCharArray()
			.Select (x  =>  keyMap[x] )
						.ToArray())))
			.Where (w  =>  w.Value==key)
			.Select (w  =>  w.Key)
			.Dump("Word suggestions");