Why hashes are used everywhere in Ruby - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a hash with a key 'name' and value 'Ruby'.

Ruby

person = { :name => [1] }

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

A"Ruby"

BRuby

C:Ruby

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put quotes around string values.

Using a symbol instead of a string for the value.

In Ruby, hash values can be strings. Here, the value for the key :name is the string "Ruby".

2fill in blank

medium

Complete the code to access the value of the key :age from the hash.

Ruby

person = { age: 25 }
age = person[[1]]

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

Aage

B"age"

C:age

D25

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string "age" instead of symbol :age.

Using the value 25 instead of the key.

To access a value in a Ruby hash using a symbol key, use the symbol :age inside the brackets.

3fill in blank

hard

Fix the error in the code to add a new key-value pair :city => 'Tokyo' to the hash.

Ruby

person = { name: "Ruby" }
person[1] = "Tokyo"

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

A.city

B[:city]

Ccity

Attempts:

3 left

💡 Hint

Common Mistakes

Using dot notation which is invalid for hashes.

Using the key without brackets.

To add or update a key-value pair in a Ruby hash, use the syntax hash[:key] = value.

4fill in blank

hard

Fill both blanks to create a hash with keys :a and :b and values 1 and 2.

Ruby

numbers = { [1]: 1, [2]: 2 }

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

Aa

B1

Cb

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using numbers as keys instead of symbols.

Putting quotes around keys.

Keys in Ruby hashes can be symbols written as :a and :b. Here, we use the shorthand syntax with keys a and b.

5fill in blank

hard

Fill all three blanks to create a hash with keys :x, :y and values 10, 20, and access the value of :y.

Ruby

coords = { [1]: [2], [3]: 20 }
y_value = coords[:y]

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

Ax

B10

Cy

D20

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up keys and values.

Using strings instead of symbols for keys.

The hash has keys :x and :y with values 10 and 20. We access the value of :y using coords[:y].