Object identity (equal? vs ==) in Ruby - Quick Revision & Key Differences

Recall & Review

beginner

What does the equal? method check in Ruby?

The equal? method checks if two variables point to the exact same object in memory. It tests object identity.

beginner

What does the == operator check in Ruby?

The == operator checks if two objects have the same value or content, not necessarily the same object in memory.

beginner

Given a = "hello" and b = "hello", what will a.equal?(b) return?

It will return false because a and b are two different string objects even though they have the same content.

beginner

Given a = "hello" and b = "hello", what will a == b return?

It will return true because a and b have the same string content.

intermediate

Why might you use equal? instead of ==?

Use equal? when you want to know if two variables are exactly the same object, not just equal in value. This is important when object identity matters.

In Ruby, which method checks if two variables refer to the same object?

A equal?

B ==

C eql?

D equals

The equal? method checks if two variables point to the exact same object in memory.

What does a == b check in Ruby?

A If a and b are the same object

B If a and b have different object ids

C If a and b have the same value

D If a and b are different classes

The == operator checks if two objects have the same value or content.

If a = "cat" and b = a, what will a.equal?(b) return?

A true

B false

C nil

D error

Since b points to the same object as a, equal? returns true.

Which method would return false for two different string objects with the same content?

A clone

B ==

C to_s

D equal?

equal? returns false because the objects are different, even if their content is the same.

What is the main difference between equal? and == in Ruby?

A <code>equal?</code> checks value, <code>==</code> checks identity

B <code>equal?</code> checks identity, <code>==</code> checks value

C Both check identity

D Both check value

equal? checks if two variables are the same object; == checks if their values are equal.

Explain the difference between equal? and == in Ruby with an example.

Think about whether two variables point to the same object or just have the same content.

When would you prefer to use equal? over == in your Ruby code?

Consider situations where knowing if two variables are exactly the same object matters.