Checking array equality

array_1 = [1, 2, 3]
array_2 = [2, 3, 1]
array_with_duplicates = [1, 1, 1, 3, 3, 2]

# Equality (with order importance)
array_1 == [1, 2, 3] #=> true
array_1 == array_2 #=> false

# Spaceship operator returns: 0 (equal), -1 (elements less than other array), 1 (elements more than other array)
(array_1 <=> array_2) == 0 #=> false

# Equality (without order importance)
array_1.sort == array_2.sort #> true
(array_1.sort <=> array_2.sort) == 0 #=> true
array_1.sort == array_with_duplicates.sort #> false

# Equality (without duplicates)
array_1.uniq.sort == array_with_duplicates.uniq.sort #> true

# Iterations, Shiterations
# Both uniq and sort will iterate the entire collection, adding to processing time.
# `#uniq` - "self is traversed in order, and the [first](https://apidock.com/ruby/Array/first) occurrence is kept."
# `#sort` - "Comparisons for the [sort](https://apidock.com/ruby/Array/sort) will be done using the <=> operator"

# Equality (without duplicates and ordering)
Set.new(array_1) == Set.new(array_2) #=> true
Set.new(array_1) == Set.new(array_with_duplicates) #=> true

# Array intersection (unique values only ordered by first collection)
# https://ruby-doc.org/3.2.2/Array.html#method-i-26
(array_1 & array_2) == array_1 #=> true
(array_1 & array_with_duplicates) == array_1 #=> true
joshmfrankel / joshmfrankel.github.io

Checking array equality #61
