# Solve FizzBuzz Using Linq Extension Methods

So if you haven’t heard of the FizzBuzz test, it’s basically taking in a list of numbers and figuring out if they are divisible, cleanly, by two numbers. Say you have 3 and 5 and this is your list:

1

3

5

10

15

If the number is divisible by 3, then return the Fizz string. If the number is divisible by 5, return a Buzz string. If it’s divisible by both, then return FizzBuzz.

1

Fizz

Buzz

Buzz

FizzBuzz

Pretty simple and in actuality pretty easy to do with old C# tools, but I wanted to do this with Linq. With the use of Funcs, Actions, and Linq extension methods it can be done fairly easily. Technically you can do the whole thing in one line if you don’t want to bother with refactoring.

I have no idea how to format this cleanly, so sorry if the format is confusing. Basically it is take a list, get the ones you want, concatenate it with the next list.

```public static IList<KeyValuePair<Int32, String>> ConvertListOfIntegersWithLinqMethods(IList<Int32> listToConvert, Int32 fizzNumber, Int32 buzzNumber)
{
var result =
listToConvert
.Where(WhereBothDivisible(fizzNumber, buzzNumber))
.Select(selectKeyValuePair("FizzBuzz"))
.Concat(
listToConvert
.Where(WhereBuzzDivisable(fizzNumber, buzzNumber))
.Select(selectKeyValuePair("Buzz")))
.Concat(
listToConvert
.Where(WhereFizzDivisable(fizzNumber, buzzNumber))
.Select(selectKeyValuePair("Fizz")))
.Concat(
listToConvert
.Where(WhereNeitherDivisable(fizzNumber, buzzNumber))
.Select(selectKeyValuePair("Nothing")));

return result.ToList().OrderBy(currentItem => currentItem.Key).ToList();
}```

Using these:

```private static Func<Int32, KeyValuePair<Int32, String>> selectKeyValuePair(String value)
{
return currentItem => new KeyValuePair<Int32, String>(currentItem, value);
}

private static Func<Int32, Boolean> WhereBothDivisible(Int32 fizzNumber, Int32 buzzNumber)
{
return  currentItem => IsDivisible(currentItem, fizzNumber) && IsDivisible(currentItem, buzzNumber);
}

private static Func<Int32, Boolean> WhereFizzDivisable(Int32 fizzNumber, Int32 buzzNumber)
{
return currentItem => IsDivisible(currentItem, fizzNumber) && !IsDivisible(currentItem, buzzNumber);
}

private static Func<Int32, Boolean> WhereBuzzDivisable(Int32 fizzNumber, Int32 buzzNumber)
{
return currentItem => !IsDivisible(currentItem, fizzNumber) && IsDivisible(currentItem, buzzNumber);
}

private static Func<Int32, Boolean> WhereNeitherDivisable(Int32 fizzNumber, Int32 buzzNumber)
{
return currentItem => !IsDivisible(currentItem, fizzNumber) && !IsDivisible(currentItem, buzzNumber);
}```