Why advanced LINQ matters in C Sharp (C#) - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select all even numbers from the list using LINQ.

C Sharp (C#)

var evens = numbers.Where(n => n [1] 2 == 0).ToList();

Drag options to blanks, or click blank then click option'

A%

B/

C*

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using division operator instead of modulo.

Using multiplication or addition operators.

The modulo operator % returns the remainder. Using n % 2 == 0 checks if a number is even.

2fill in blank

medium

Complete the code to order the list of strings by their length using LINQ.

C Sharp (C#)

var ordered = words.OrderBy(w => w.[1]).ToList();

Drag options to blanks, or click blank then click option'

ACount

BLength

CSize

DLength()

Attempts:

3 left

💡 Hint

Common Mistakes

Using Length() as if it were a method.

Using Count which is for collections, not strings.

Strings have a property Length that gives their length. Use it without parentheses.

3fill in blank

hard

Fix the error in the LINQ query to select distinct names from the list.

C Sharp (C#)

var distinctNames = names.[1]().ToList();

Drag options to blanks, or click blank then click option'

AUnique

BUniqueNames

CDifferent

DDistinct

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent methods like Unique or Different.

The correct LINQ method to get unique elements is Distinct().

4fill in blank

hard

Fill both blanks to create a dictionary with words as keys and their lengths as values, filtering words longer than 3 characters.

C Sharp (C#)

var dict = words.Where(w => w.[1] 3).ToDictionary(w => w, w => w.[2]);

Drag options to blanks, or click blank then click option'

A>

B<

CLength

DCount

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > for filtering.

Using Count instead of Length for strings.

We filter words longer than 3 using > 3 and use the Length property for values.

5fill in blank

hard

Fill all three blanks to create a dictionary with uppercase words as keys, their original words as values, filtering words starting with 'a'.

C Sharp (C#)

var dict = words.Where(w => w.[1]('a')).ToDictionary(w => w.[2](), w => w.[3]);

Drag options to blanks, or click blank then click option'

AStartsWith

BToUpper

CToString

DLength

Attempts:

3 left

💡 Hint

Common Mistakes

Using Length instead of ToString for values.

Using wrong methods for filtering or converting case.

We filter words starting with 'a' using StartsWith, convert keys to uppercase with ToUpper(), and use the original word as value with ToString().