Ruby arrays can hold multiple data types

by Jii Yoo
…
Note
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Writing

Ruby arrays appear to store different data types, but under the hood, they actually store references to objects.

Here’s an example of a Ruby array containing various types:

def foo()
	'function'
end

list = [17, "seventeen", 1.7, true, false, foo, nil]

This is perfectly valid Ruby code. But how does Ruby allow this?

Unlike arrays in statically-typed languages like C or C++, where arrays are strictly typed, Ruby arrays are dynamic. Rather than storing raw values directly, a Ruby array holds references to objects, allowing it to contain elements of different types (we can simulate the same behavior in C using pointers (250201115105)).

Everything in Ruby is an object—even primitive values like integers (Integer), booleans (TrueClass/FalseClass), and nil (NilClass).

Let’s verify this by checking the class of each element:

list.each { |elem| puts elem.class }

# --- output
# Integer  
# String  
# Float  
# TrueClass  
# FalseClass  
# String  
# NilClass

Since everything is an object, Ruby arrays store references to objects, making them flexible and dynamic.

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