Symbol type and immutability in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a symbol named :apple.

Ruby

fruit = [1]

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

A'apple'

B:apple

Capple

D"apple"

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes creates a string, not a symbol.

Leaving out the colon creates a variable or method name.

The colon : before a word creates a symbol in Ruby. So :apple is a symbol.

2fill in blank

medium

Complete the code to check if two symbols are the same object.

Ruby

puts :cat.[1] :cat

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

A!=

B==

Ceql?

Dequal?

Attempts:

3 left

💡 Hint

Common Mistakes

Using == checks value equality but not object identity.

Using != is for inequality.

The equal? method checks if two objects are the exact same object in memory. Symbols with the same name are the same object.

3fill in blank

hard

Fix the error in the code to convert a string to a symbol.

Ruby

sym = "dog".[1]

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

Ato_sym!

Bto_s

Cto_sym

Dto_str

Attempts:

3 left

💡 Hint

Common Mistakes

Using to_s returns a string, not a symbol.

There is no to_sym! method.

The method to_sym converts a string to a symbol in Ruby.

4fill in blank

hard

Fill both blanks to create a hash with symbol keys and access a value.

Ruby

person = { [1] => "Alice", [2] => 30 }
age = person[:age]

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

A:name

B:age

C"age"

D"name"

Attempts:

3 left

💡 Hint

Common Mistakes

Using strings as keys when symbols are expected.

Mixing symbol and string keys inconsistently.

Symbols are used as keys in hashes for efficiency. Here, :name and :age are symbol keys.

5fill in blank

hard

Fill all three blanks to demonstrate symbol immutability and comparison.

Ruby

sym1 = :car
sym2 = :car
puts sym1 [1] sym2
puts sym1.object_id [2] sym2.object_id
# Trying to change symbol (will cause error)
sym3 = :bike
# sym3 [3] "cycle" # Uncommenting causes error

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

A==

B!=

D=

Attempts:

3 left

💡 Hint

Common Mistakes

Using inequality operators when equality is expected.

Trying to modify a symbol with methods like replace which do not exist.

Symbols with the same name are equal and share the same object id. Symbols cannot be changed once created, so assignment is the only way to set a symbol variable.