koobas.hobune.stream
How can I simplify a nested foreach
I think I took longer to try to think of a title that summarized this than I did on explaining the actual problem. x_x
I have a function with nested foreach loops that I would like to simplify or at least make re-usable. In this sample, each friends property is of type List<Person>.
void InviteFriendsToParty(Person p) {
foreach (Person e in p.friends)
foreach (Person r in e.friends)
foreach (Person s in r.friends)
foreach (Person o in s.friends)
SendInvitation(o); }
Is it possible to convert this to such a function that I can pass in a source Person p and an int depth and let the nested foreach part be dynamically sized? I've tried a couple of variations, but I think I've been trying to overcomplicate it for so long that I'm missing something really simple.
Something like this could work
void InviteFriendsToParty(Person p, int depth) {
foreach (Person e in p.friends) {
if (depth == 0) {
SendInvitation(e);
} else {
InviteFriendsToParty(e, --depth);
}
}
}
You could make it more reusableby parameterizing the function that should be called at the end.
void DoToFriendsRecursive(Person p, Action<Person> action, int depth) {
foreach (Person e in p.friends) {
if (depth == 0) {
action(e);
} else {
DoToFriendsRecursive(e, action, --depth);
}
}
}
I'm just guessing here but you probably need either a depth limit like in my example or some way to detect and terminate endless loops. If A is friend of B who's friend of C who's friend of A, they will send invites in a circle unless you specifically stop it
Awesome. This worked perfectly, with 1 exception. If I pass depth-- into the recursive function, I get StackOverflowException. Changing this to depth-1 however seems to fix it entirely. Fast and concise.
Thank you very much. :)
Lol. Of course X-)... depth-- passes forward the non-decremented value. It should work with --depth too. Answer edited.
Glad to be of help.
