Is there an array method to return the how many elements are a value of 1?

Question

Hi With c# the array Max Min and Average Methods are brilliant for working out those things as needs. But also does anyone know if there is an array method that tells you the number of elements that are equal to a certain value. For example I've written a little app which computes the number of times it will takes to get 3 in a line when playing a slot machine. So far I've found that it would take an average 80 attempts to hit a jackpot. Out of curiosity I would like to know how many elements of my array are equal to one. In other words this would mean that someone has got two Jackpots in a row!! I've seen it done quite a few times!! Anyway does anyone know if there is an array method that tells you the number of elements that are equal to a certain value? for example how many array elements are equal to 1. cheers Matt

Vulpes · Answer

Just remembered that the Count() extension method has an overload which takes a predicate i.e. an expression which is either true or false. So in the above program you could replace: return ia.Where(i => i == number).Count(); with simply this: return ia.Count(i => i == number);

Vulpes · Answer

Good luck with the interview :)

Matt Higgins · Answer

hi Vulpes I've just bought a book - I think I will get my next employer to treat me to one next or wait until Christmas. The books you recommend seem a little pricy which is the only obstacle. I've also got an interview tomorrow for a c# developer position so I'm just keeping my fingers crossed for now. Cheers Matt

Vulpes · Answer

As far as .NET and C# are concerned I'm self-taught having used them since the beta of version 1.0 back in 2001. However there are several books which have helped me along the way. I'll single out a couple (latest versions) which I'd recommend any C# developer to read or to have available as a reference: http://www.amazon.com/C-5-0-Nutshell-Definitive-Reference/dp/1449320104 http://www.amazon.com/CLR-via-C-Jeffrey-Richter/dp/0735627045

Matt Higgins · Answer

Thanks Vulpes Can I ask - how did you become so good at programming? Is there any books or courses you've been on which really helped you along? Cheers Matt

Vulpes · Answer

There isn't such a method in the .NET framework but it's easy to write one using LINQ: using System; using System.Linq; class Test { static void Main() { int[] ia = {1 2 1 1 4 1}; Console.WriteLine(GetFrequency(ia 1)); // 4 Console.ReadKey(); } static int GetFrequency(int[] ia int number) { return ia.Where(i => i == number).Count(); } }