Ruby 2.4 includes several new features such as a #sum method for Enumerable to calculate the sum of elements, faster Array#min and Array#max methods, extracting named captures from regular expression matches, testing if directories and files are empty, a new Integer#digits method to return digits as an array, and simplifying the numeric class hierarchy by removing Fixnum. Additional changes include faster regular expression matching with Regexp#match?, moving Logger configuration to its constructor, and supporting new arguments for float modifiers like ceil, floor, truncate and round.

1. New Features
in Ruby 2.4
Ireneusz Skrobiś
Lead Developer @ Selleo

2. New #sum method for Enumerable

3. New #sum method for Enumerable
[1, 1, 2, 3, 5, 8, 13, 21].sum # => 54

4. New #sum method for Enumerable
[1, 1, 2, 3, 5, 8, 13, 21].sum # => 54
The #sum method has an optional parameter which defaults to 0.
This value is the starting value of a summation meaning that [].sum is 0.

5. Faster Array#min and Array#max

6. Faster Array#min and Array#max
Array#min: 35.1 i/s
Enumerable#min: 21.8 i/s - 1.61x slower

7. Extract named captures from Regexp match results

8. Extract named captures from Regexp match results
pattern = /(?<first_name>John) (?<last_name>w+)/
pattern.match('John Backus').named_captures
# => {"first_name" => "John", "last_name" => "Backus"}

9. Extract named captures from Regexp match results
pattern = /(?<first_name>John) (?<last_name>w+)/
pattern.match('John Backus').named_captures
# => {"first_name" => "John", "last_name" => "Backus"}
pattern =
/(?<year>d{4})-(?<month>d{2})-(?<day>d{2})/
pattern.match('2016-02-01').values_at(:year, :month)
# => ["2016", "02"]

10. Faster regular expressions with Regexp#match?

11. Faster regular expressions with Regexp#match?
Regexp#match?: 2630002.5 i/s
Regexp#===: 872217.5 i/s - 3.02x slower
Regexp#=~: 859713.0 i/s - 3.06x slower
Regexp#match: 539361.3 i/s - 4.88x slower

12. New methods for testing if directories/files are empty

13. New methods for testing if directories/files are empty
Dir.empty?('empty_directory') # => true
Dir.empty?('directory_with_files') # => false
File.empty?('contains_text.txt') # => false
File.empty?('empty.txt') # => true

14. New Integer#digits method

15. New Integer#digits method
123.digits # => [3, 2, 1]
123.digits[0] # => 3

16. New Integer#digits method
123.digits # => [3, 2, 1]
123.digits[0] # => 3
# Equivalent behavior in Ruby 2.3:
123.to_s.chars.map(&:to_i).reverse # => [3, 2, 1]

17. Moves configuration to Logger’s constructor

18. Moves configuration to Logger’s constructor
logger = Logger.new(STDOUT, level: :info, progname: 'LOG')

19. Moves configuration to Logger’s constructor
logger = Logger.new(STDOUT, level: :info, progname: 'LOG')
# Equivalent behavior in Ruby 2.3:
logger = Logger.new(STDOUT)
logger.level = :info
logger.progname = 'LOG'

20. Simplified integers

21. Simplified integers
# Find classes which subclass the base "Numeric" class:
numerics = ObjectSpace.each_object(Module).select { |mod| mod < Numeric }

22. Simplified integers
# Find classes which subclass the base "Numeric" class:
numerics = ObjectSpace.each_object(Module).select { |mod| mod < Numeric }
# In Ruby 2.3:
numerics # => [Complex, Rational, Bignum, Float, Fixnum, Integer, BigDecimal]

23. Simplified integers
# Find classes which subclass the base "Numeric" class:
numerics = ObjectSpace.each_object(Module).select { |mod| mod < Numeric }
# In Ruby 2.3:
numerics # => [Complex, Rational, Bignum, Float, Fixnum, Integer, BigDecimal]
# In Ruby 2.4:
numerics # => [Complex, Rational, Float, Integer, BigDecimal]

24. New arguments supported for float modifiers

25. New arguments supported for float modifiers
4.55.ceil(1) # => 4.6
4.55.floor(1) # => 4.5
4.55.truncate(1) # => 4.5
4.55.round(1) # => 4.6

26. You can find more information here
https://blog.blockscore.com/new-features-in-ruby-2-4/

27. Thank you!
Live long and prosper :)
Ireneusz Skrobiś
Lead Developer @ Selleo