In this post we will review a bunch of small and simple LINQ interview questions to get you started. Once you understand these standard query expressions, it should be a breeze for you to answer LINQ questions.
Question: Given an array of numbers, find if ALL numbers are a multiple of a provided number. For example, all of the following numbers - 30, 27, 15, 90, 99, 42, 75 are multiples of 3.
The trick here is to use the Enumerable.All<TSource> method which determines whether all elements of a sequence satisfy a condition.
static void Main(string[] args)
{
int[] numbers = { 30, 27, 15, 90, 99, 42, 75 };
bool isMultiple = MultipleTester(numbers, 3);
}
private static bool MultipleTester(int[] numbers, int divisor)
{
bool isMultiple =
numbers.All(number => number % divisor == 0);
return isMultiple;
}
Question: Given an array of numbers, find if ANY of the number is divisible by 5. For example, one of the following numbers - 30, 27, 18, 92, 99, 42, 72 is divisible by 5.
Again, the key fact here is to use Enumerable.Any<TSource> method which determines whether any element of a sequence satisfies a condition. The code is very similar to the ALL case.
static void Main(string[] args)
{
int[] numbers = { 30, 27, 18, 92, 99, 42, 72 };
bool isDivisible = IsDivisible(numbers, 3);
}
private static bool IsDivisible(int[] numbers, int divisor)
{
bool isDivisible =
numbers.Any(number => number % divisor == 0);
return isDivisible;
}
Another way to present a similar question that utilizes Enumerable.Any<TSource> method is shown below.
Question: Given a GPSManufacturer and GPSDevice data structure as defined below, find all the manufacturers that have at least 1 or more active GPS devices.
class GpsDevice
{
public string Name;
public bool IsActive;
}
Read more: Programming Interviews Series Part 1, Part 2
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