Proc vs lambda differences (arity, return) in Ruby - Quick Revision & Key Differences

Recall & Review

beginner

What is a Proc in Ruby?

A Proc is a block of code that can be stored in a variable and called later. It behaves like a method but is more flexible and can be passed around.

intermediate

How does a lambda handle the number of arguments (arity) compared to a Proc?

A lambda checks the number of arguments strictly and raises an error if the count doesn't match. A Proc is more lenient and ignores extra arguments or assigns nil to missing ones.

intermediate

What happens when you use return inside a lambda vs inside a Proc?

Inside a lambda, return exits only from the lambda itself. Inside a Proc, return exits from the method enclosing the Proc, which can cause unexpected behavior.

beginner

Which behaves more like a method: Proc or lambda?

A lambda behaves more like a method because it checks arguments strictly and its return exits only from itself, not the enclosing method.

beginner

How do you create a lambda and a Proc in Ruby?

You create a lambda with lambda { |args| ... } or ->(args) { ... }. You create a Proc with Proc.new { |args| ... } or proc { |args| ... }.

What happens if you pass the wrong number of arguments to a lambda?

A It assigns nil to missing arguments

B It ignores extra arguments

C It runs without any checks

D It raises an error

A lambda strictly checks the number of arguments and raises an error if they don't match.

What does return inside a Proc do?

A Exits the enclosing method

B Exits only the Proc

C Raises an error

D Does nothing

A return inside a Proc exits the method that contains the Proc, not just the Proc itself.

Which one behaves more like a method in Ruby?

A lambda

B Neither

C Both behave the same

D Proc

A lambda behaves more like a method because it checks arguments and handles return differently.

How do you create a lambda in Ruby?

A Proc.new { ... }

B lambda { ... }

C def lambda ... end

D create_lambda { ... }

You create a lambda using the keyword lambda or the arrow syntax ->.

If a Proc receives fewer arguments than expected, what happens?

A It ignores missing arguments

B It raises an error

C It assigns nil to missing arguments

D It stops execution

A Proc assigns nil to any missing arguments instead of raising an error.

Explain the differences between Proc and lambda in Ruby regarding argument handling and return behavior.

Think about how each handles wrong number of arguments and where return goes.

Describe how you create and use a Proc and a lambda in Ruby with examples.

Show simple code snippets and explain behavior.