Proc vs lambda differences (arity, return) in Ruby - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a lambda that takes one argument.

Ruby

my_lambda = [1] do |x|
  x * 2
end

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

Alambda

Bproc

CProc.new

Ddef

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'proc' instead of 'lambda' which does not enforce arity.

Using 'Proc.new' which creates a proc, not a lambda.

In Ruby, lambda creates a lambda object that checks the number of arguments (arity).

2fill in blank

medium

Complete the code to create a proc that ignores extra arguments.

Ruby

my_proc = [1] do |x|
  x + 1
end

puts my_proc.call(5, 10)

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

Alambda

Bdef

CProc.new

Dproc

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'lambda' which enforces exact number of arguments.

Using 'def' which defines a method, not a proc.

Using proc creates a proc that does not enforce the number of arguments strictly.

3fill in blank

hard

Fix the error in the code by choosing the correct keyword to create a lambda.

Ruby

my_func = [1] do |x, y|
  return x + y
end

puts my_func.call(2, 3)

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

Alambda

BProc.new

Cproc

Ddef

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'proc' which causes 'return' to exit the enclosing method.

Using 'Proc.new' which behaves like 'proc'.

Only lambda treats return as returning from the lambda itself, not the enclosing method.

4fill in blank

hard

Fill both blanks to create a proc and call it with two arguments, ignoring extra ones.

Ruby

my_proc = [1] do |a, b|
  a - b
end

puts my_proc.call(10, 5, [2])

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

Aproc

Blambda

C20

D30

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'lambda' which enforces exact arguments and will raise an error.

Passing no extra argument which misses the point of ignoring extras.

Using proc allows extra arguments to be ignored. The third argument '20' is ignored.

5fill in blank

hard

Fill all three blanks to create a lambda, call it with correct arguments, and return the sum.

Ruby

my_lambda = [1] do |x, y|
  [2] x + y
end

result = my_lambda.call([3], 7)
puts result

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

Alambda

Breturn

C5

Dproc

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'proc' which treats return differently.

Omitting 'return' which still works but is less explicit.

Using lambda with return returns from the lambda itself. Calling with 5 and 7 sums to 12.