Skip to content
Permalink
master
Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
Go to file
 
 
Cannot retrieve contributors at this time
executable file 65 lines (49 sloc) 1.64 KB
#!/usr/bin/env ruby
# Companion source code to blog article at:
# https://bbs-software.com/blog/2019/11/13/enumerables-short-and-sweet.html
require 'yaml'
def filtered_and_transformed_records_1(records)
results = []
records.each do |record|
next unless record.vowel?
results << [record.letter, record.frequency]
end
results
end
def filtered_and_transformed_records_2(records)
records.each_with_object([]) do |record, results|
next unless record.vowel?
results << [record.letter, record.frequency]
end
end
def filtered_and_transformed_records_3(records)
records.select(&:vowel?).each_with_object([]) do |record, results|
results << [record.letter, record.frequency]
end
end
def filtered_and_transformed_records_4(records)
records.select(&:vowel?).map { |record| [record.letter, record.frequency] }
end
LetterFrequency = Struct.new(:letter, :frequency, :vowel?)
RECORDS = [
LetterFrequency.new('a', 15, true),
LetterFrequency.new('b', 4, false),
LetterFrequency.new('c', 7, false),
LetterFrequency.new('d', 6, false),
LetterFrequency.new('e', 32, true),
LetterFrequency.new('f', 3, false),
LetterFrequency.new('i', 18, true),
LetterFrequency.new('o', 19, true),
LetterFrequency.new('u', 4, true),
LetterFrequency.new('z', 0, false),
]
a1 = filtered_and_transformed_records_1(RECORDS)
a2 = filtered_and_transformed_records_2(RECORDS)
a3 = filtered_and_transformed_records_3(RECORDS)
a4 = filtered_and_transformed_records_4(RECORDS)
all_equal = [a2, a3, a4].all? { |a| a == a1 }
if all_equal
puts "All arrays were equal:\n\n#{a1.to_yaml}"
else
raise "Error; arrays were not equal."
end