Object#clone
obj.clone -> obj Returns:
obj · Updated March 13, 2026 · Core Classes objects copy duplication
clone creates a shallow copy of an object. Unlike dup, it also copies the object’s singleton class (methods defined on that specific object) and preserves the frozen status.
Syntax
obj.cloneParameters
clone accepts no parameters.
Examples
Basic usage
original = "hello"
copy = original.clone
original << " world"
puts original # => "hello world"
puts copy # => "hello"Preserving freeze status
original = "immutable".freeze
copy_clone = original.clone
# clone preserves frozen status
puts copy_clone.frozen? # => trueCloning with singleton methods
obj = Object.new
def obj.greet; "hello"; end
cloned = obj.clone
cloned.respond_to?(:greet) # => true
# dup would not include the greet methodCloning an array
original = [1, 2, [3, 4]]
copy = original.clone
original[2] << 5
puts original.inspect # => [1, 2, [3, 4, 5]]
puts copy.inspect # => [1, 2, [3, 4, 5]] - nested array is shared!Frozen string literals
In Ruby 3.0+, strings from frozen string literals are frozen by default. When you clone a frozen string, the copy remains frozen:
frozen = "frozen".freeze
puts frozen.clone.frozen? # => true (still frozen)This matters when working with immutable data patterns or performance optimization with frozen strings.
Errors
TypeError— If the object is uncloneable (some special objects like symbols before Ruby 3.0).