Object identity (equal? vs ==) in Ruby - Visual Side-by-Side Comparison

Concept Flow - Object identity (equal? vs ==)

Create obj1

↓

Create obj2

↓

Compare obj1 == obj2?

↓

Compare obj1.equal?(obj2)?

This flow shows creating two objects and comparing them using == and equal? to check value equality vs object identity.

Execution Sample

Ruby

obj1 = "hello"
obj2 = "hello"
puts obj1 == obj2
puts obj1.equal?(obj2)

Creates two string objects with same content, compares with == and equal? to show difference.

Execution Table

Step	Action	obj1	obj2	obj1 == obj2	obj1.equal?(obj2)	Output
1	Create obj1 = "hello"	"hello" (obj1)	-	-	-	-
2	Create obj2 = "hello"	"hello" (obj1)	"hello" (obj2)	-	-	-
3	Compare obj1 == obj2	"hello" (obj1)	"hello" (obj2)	true	-	true
4	Compare obj1.equal?(obj2)	"hello" (obj1)	"hello" (obj2)	-	false	false
5	End	"hello" (obj1)	"hello" (obj2)	true	false	-

💡 Comparison ends after checking both == and equal? methods.

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
obj1	nil	"hello" (obj1)	"hello" (obj1)	"hello" (obj1)
obj2	nil	nil	"hello" (obj2)	"hello" (obj2)

Key Moments - 2 Insights

Why does obj1 == obj2 return true but obj1.equal?(obj2) return false?

Because == checks if the content or value is the same (see step 3), while equal? checks if both variables point to the exact same object in memory (step 4). Here, obj1 and obj2 have same content but are different objects.

Can two different objects have the same value in Ruby?

Yes, as shown in step 2 and 3, obj1 and obj2 are different objects but have identical string content, so == returns true but equal? returns false.

Visual Quiz - 3 Questions

Look at the execution table at step 3, what does obj1 == obj2 evaluate to?

A true

B false

C nil

D error

💡 Hint

Check the 'obj1 == obj2' column in row for step 3 in execution_table.

At which step does obj1.equal?(obj2) get evaluated?

A Step 2

B Step 4

C Step 3

D Step 5

💡 Hint

Look at the 'Action' column in execution_table to find when equal? is called.

If obj2 was assigned as obj2 = obj1, what would obj1.equal?(obj2) return?

A nil

B false

C true

D error

💡 Hint

Refer to variable_tracker to see that both variables point to the same object if assigned directly.

Concept Snapshot

In Ruby:
- == checks if two objects have the same value/content.
- equal? checks if two variables point to the exact same object.
- Different objects can be == true but equal? false.
- Use equal? to test object identity, == for value equality.

Full Transcript

This example creates two string objects obj1 and obj2 with the same content "hello". When comparing with ==, Ruby checks if their values are equal, which is true. But equal? checks if both variables point to the same object in memory, which is false here because they are separate objects. This shows the difference between value equality and object identity in Ruby.