Dictionary methods and access patterns in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a new key-value pair to the dictionary.

C Sharp (C#)

var dict = new Dictionary<string, int>();
dict.[1]("apple", 5);

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

AAdd

BInsert

CPut

DSet

Attempts:

3 left

💡 Hint

Common Mistakes

Using Insert or Set which are not valid Dictionary methods.

Trying to assign directly without using a method.

The Add method is used to add a new key-value pair to a Dictionary in C#.

2fill in blank

medium

Complete the code to check if the dictionary contains the key "banana".

C Sharp (C#)

var dict = new Dictionary<string, int> { {"banana", 3} };
bool hasKey = dict.[1]("banana");

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AContainsKey

BContainsValue

CHasKey

DExists

Attempts:

3 left

💡 Hint

Common Mistakes

Using ContainsValue which checks for values, not keys.

Using non-existent methods like HasKey or Exists.

ContainsKey checks if a specific key exists in the dictionary.

3fill in blank

hard

Fix the error in the code to safely get the value for key "orange".

C Sharp (C#)

var dict = new Dictionary<string, int> { {"orange", 7} };
int value;
if (dict.[1]("orange", out value)) {
    Console.WriteLine(value);
}

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AGetOrDefault

BGetValue

CContainsKey

DTryGetValue

Attempts:

3 left

💡 Hint

Common Mistakes

Using ContainsKey which only checks existence but does not get the value.

Using non-existent methods like GetValue or GetOrDefault.

TryGetValue tries to get the value for a key and returns true if found.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps words to their lengths if length is greater than 3.

C Sharp (C#)

var words = new List<string> { "cat", "house", "dog", "elephant" };
var lengths = words.Where(word => word.[1] > 3)
                   .ToDictionary(word => word, word => word.[2]);

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ALength

BCount

CSize

DLength()

Attempts:

3 left

💡 Hint

Common Mistakes

Using Length() which is invalid because Length is a property, not a method.

Using Count or Size which do not exist for strings.

The Length property gives the number of characters in a string in C#.

5fill in blank

hard

Fill all three blanks to create a dictionary from a list of tuples filtering only those with value greater than 10.

C Sharp (C#)

var data = new List<(string, int)> { ("a", 5), ("b", 15), ("c", 20) };
var filtered = data.Where(item => item.[1] > 10)
                   .ToDictionary(item => item.[2], item => item.[3]);

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AItem2

BItem1

DValue

Attempts:

3 left

💡 Hint

Common Mistakes

Using Value which is not a tuple property.

Mixing up Item1 and Item2 positions.

Tuples use Item1 for the first element and Item2 for the second element in C#.