lazy or not lazy

lazy.rb

# frozen_string_literal: true

require 'memory_profiler'
require 'resolv'

report = MemoryProfiler.report do
  # $ wc -l development.log
  # 1000000 development.log
  open('development.log') do |f|
    f
      .each_line
      .lazy
      .map { |line| line.scrub('?') } # avoid invalid byte sequence in UTF-8
      .map { |line| line[/\d{1,3}\.\d{1,3}\.\d{1,3}.\d{1,3}/] }
      .select { |ip_addr| ip_addr }
      .take(100)
  end
end

report.pretty_print
# Total allocated: 3080 bytes (38 objects)

not_lazy.rb

# frozen_string_literal: true

require 'memory_profiler'
require 'resolv'

report = MemoryProfiler.report do
  # $ wc -l development.log
  # 1000000 development.log
  open('development.log') do |f|
    f
      .each_line
      .map { |line| line.scrub('?') } # avoid invalid byte sequence in UTF-8
      .map { |line| line[/\d{1,3}\.\d{1,3}\.\d{1,3}.\d{1,3}/] }
      .select { |ip_addr| ip_addr }
      .take(100)
  end
end

report.pretty_print
# Total allocated: 319791009 bytes (3024548 objects)