Effective way of String splitting

Question

I have a completed string like this

N:Pay in Cash++RGI:40++R:200++T:Purchase++IP:N++IS:N++PD:PC++UCP:598.80++UPP:0.00++TCP:598.80++TPP:0.00++QE:1++QS:1++CPC:USD++PPC:Points++D:Y++E:Y++IFE:Y++AD:Y++IR:++MV:++CP:~~ N:ERedemption++RGI:42++R:200++T:Purchase++IP:N++IS:N++PD:PC++UCP:598.80++UPP:0.00++TCP:598.80++TPP:0.00++QE:1++QS:1++CPC:USD++PPC:Points++D:Y++E:Y++IFE:Y++AD:Y++IR:++MV:++CP:

this string is like this

1. It's list of PO's(Payment Options) which are separated by ~~
2. this list may contains one or more OP
3. PO contains only Key-Value Pairs which separated by :
4. spaces are denoted by ++

I need to extract the values for Key "RGI" and "N".

I can do it via for loop , I want a efficient way to do this. any help on this.

Edit: from ~ ~ To ~~

Answer 1

hear ya go I used regular expressions and for a reasonable amount of text they preform well.

 static void Main(string[] args)
{
    string str = @"N:Pay in Cash++RGI:40++R:200++T:Purchase++IP:N++IS:N++PD:PC++UCP:598.80++UPP:0.00++TCP:598.80++TPP:0.00++QE:1++QS:1++CPC:USD++PPC:Points++D:Y++E:Y++IFE:Y++AD:Y++IR:++MV:++CP:~ ~N:ERedemption++RGI:42++R:200++T:Purchase++IP:N++IS:N++PD:PC++UCP:598.80++UPP:0.00++TCP:598.80++TPP:0.00++QE:1++QS:1++CPC:USD++PPC:Points++D:Y++E:Y++IFE:Y++AD:Y++IR:++MV:++CP:"; 
    System.Text.RegularExpressions.MatchCollection MC = System.Text.RegularExpressions.Regex.Matches(str,@"((RGI|N):.*?)\+\+");
    foreach( Match Foundmatch in MC)
    {
        string[] s = Foundmatch.Groups[1].Value.Split(':');
        Console.WriteLine("Key {0} Value {1} " ,s[0],s[1]);

    }

}