Method chaining patterns in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is method chaining in Ruby?

Method chaining is a technique where multiple methods are called in a single line, one after another, because each method returns an object that the next method can use.

beginner

Why do methods need to return self or an object for chaining to work?

For chaining, each method must return an object (often self) so the next method can be called on that returned object, allowing the chain to continue.

beginner

Example: What does this Ruby code do?

"hello".upcase.reverse

It converts "hello" to uppercase "HELLO" with upcase, then reverses it to "OLLEH" with reverse, chaining two methods in one line.

intermediate

How can method chaining improve code readability?

Method chaining lets you write clear, concise code by linking related operations in one line, making the flow easier to follow like a step-by-step recipe.

intermediate

What is a common pattern to enable method chaining in your own Ruby classes?

Define methods that perform actions and return self at the end, so you can chain multiple method calls on the same object.

In Ruby, what must a method return to allow chaining?

A An object (often self)

B nil

C A string only

D An integer

For chaining, each method must return an object so the next method can be called on it.

What will this Ruby code output?

"ruby".capitalize.reverse

A "Ybur"

B "ybuR"

C "Ruby"

D "ybur"

capitalize makes "Ruby", then reverse flips it to "ybuR" (case sensitive).

Which of these is a benefit of method chaining?

A More lines of code

B Less flexible code

C Slower execution

D Improved readability

Method chaining improves readability by linking related operations clearly.

How do you enable method chaining in your own Ruby class methods?

A Return a new object every time

B Return nil

C Return self at the end of methods

D Use global variables

Returning self allows the next method to be called on the same object.

What does this chained call do?

[1, 2, 3].map(&:to_s).join(",")

A Converts numbers to strings and joins them with commas

B Adds numbers together

C Sorts the array

D Removes duplicates

map(&:to_s) converts each number to a string, then join(",") combines them with commas.

Explain how method chaining works in Ruby and why returning self is important.

Think about how one method's output becomes the next method's input.

Describe a simple example of method chaining with strings in Ruby and what the output would be.

Use a string and two methods that change it step by step.