Proc creation and call in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Proc in Ruby?

A Proc is an object that holds a block of code which can be stored in a variable and called later.

beginner

How do you create a Proc in Ruby?

You create a Proc by using Proc.new { ... } or the shorthand proc { ... }.

beginner

How do you call a Proc once it is created?

You call a Proc using proc_object.call(arguments).

intermediate

What happens if you call a Proc with the wrong number of arguments?

A Proc is flexible and does not raise an error if called with fewer or more arguments than expected. Missing arguments become nil.

intermediate

Difference between Proc and lambda in Ruby?

A Proc is more lenient with arguments and returns from the calling method, while a lambda checks arguments strictly and returns from itself.

How do you create a Proc object in Ruby?

A proc = function() { puts 'Hello' }

B def proc { puts 'Hello' }

C create Proc { puts 'Hello' }

D Proc.new { puts 'Hello' }

You create a Proc using Proc.new with a block, like Proc.new { puts 'Hello' }.

How do you execute the code inside a Proc named 'p'?

A p.call()

B execute p()

C call p()

D p.run()

You call a Proc using the call method: p.call().

What happens if you call a Proc with fewer arguments than it expects?

A Missing arguments become nil

B It raises an error

C It ignores extra arguments

D It converts arguments to strings

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

Which of these is true about Procs compared to lambdas?

A Procs check argument count strictly

B Procs return from the calling method

C Procs cannot be stored in variables

D Procs are not objects

Procs return from the calling method, unlike lambdas which return from themselves.

Which syntax creates a Proc using shorthand in Ruby?

A lambda { puts 'Hi' }

B Proc.new do puts 'Hi' end

C proc { puts 'Hi' }

D def proc; puts 'Hi'; end

The shorthand to create a Proc is using proc { ... }.

Explain how to create and call a Proc in Ruby with an example.

Think about how you store a block of code and run it later.

Describe the difference between a Proc and a lambda in Ruby.

Focus on how they treat arguments and return statements.