Set operations (Union, Intersect, Except) in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the Union operation do in set operations?

Union combines all unique elements from two sets into one set, without duplicates.

beginner

Explain the Intersect operation in set operations.

Intersect returns only the elements that are present in both sets.

beginner

What does the Except operation do in set operations?

Except returns elements from the first set that are not in the second set.

intermediate

In C#, which method is used to perform a union of two sets?

The Union() method from System.Linq namespace is used to combine two sets without duplicates.

intermediate

How does Intersect() behave when one of the sets is empty?

The result is an empty set because there are no common elements.

Which set operation returns elements only found in the first set but not in the second?

A Intersect

B Except

C Union

D Concat

Except returns elements from the first set that are not present in the second set.

What will setA.Union(setB) return?

A All unique elements from both setA and setB

B Only elements common to setA and setB

C Elements only in setA

D Elements only in setB

Union combines all unique elements from both sets.

If setA is {1, 2, 3} and setB is {3, 4, 5}, what does setA.Intersect(setB) return?

A {3}

B {1, 2, 3, 4, 5}

C {4, 5}

D {1, 2}

Intersect returns elements common to both sets, which is {3}.

Which namespace must be included to use Union(), Intersect(), and Except() in C#?

A System.Collections.Generic

B System.IO

C System.Text

D System.Linq

These methods are extension methods in the System.Linq namespace.

What is the result of setA.Except(setB) if setA is empty?

A All elements of setA

B All elements of setB

C Empty set

D Null

Except returns elements in setA not in setB. If setA is empty, the result is empty.

Describe how the Union, Intersect, and Except operations work with examples in C#.

Think about combining, overlapping, and subtracting sets.

Explain why the System.Linq namespace is important for set operations in C#.

Consider where these methods come from.