Given a phrase, count the occurrences of each word in that phrase.
For example for the input "olly olly in come free"
olly: 2
in: 1
come: 1
free: 1
For installation and learning resources, refer to the exercism help page.
For running the tests provided, you will need the Minitest gem. Open a terminal window and run the following command to install minitest:
gem install minitest
If you would like color output, you can require 'minitest/pride'
in
the test file, or note the alternative instruction, below, for running
the test file.
Run the tests from the exercise directory using the following command:
ruby word_count_test.rb
To include color from the command line:
ruby -r minitest/pride word_count_test.rb
This is a classic toy problem, but we were reminded of it by seeing it in the Go Tour.
It's possible to submit an incomplete solution so you can see how others have completed the exercise.
require 'minitest/autorun'
require_relative 'word_count'
# Common test data version: 1.0.0 cd26d49
class WordCountTest < Minitest::Test
def test_count_one_word
# skip
phrase = Phrase.new("word")
counts = {"word"=>1}
assert_equal counts, phrase.word_count
end
def test_count_one_of_each_word
skip
phrase = Phrase.new("one of each")
counts = {"one"=>1, "of"=>1, "each"=>1}
assert_equal counts, phrase.word_count
end
def test_multiple_occurrences_of_a_word
skip
phrase = Phrase.new("one fish two fish red fish blue fish")
counts = {"one"=>1, "fish"=>4, "two"=>1, "red"=>1, "blue"=>1}
assert_equal counts, phrase.word_count
end
def test_handles_cramped_lists
skip
phrase = Phrase.new("one,two,three")
counts = {"one"=>1, "two"=>1, "three"=>1}
assert_equal counts, phrase.word_count
end
def test_handles_expanded_lists
skip
phrase = Phrase.new("one,\ntwo,\nthree")
counts = {"one"=>1, "two"=>1, "three"=>1}
assert_equal counts, phrase.word_count
end
def test_ignore_punctuation
skip
phrase = Phrase.new("car: carpet as java: javascript!!&@$%^&")
counts = {"car"=>1, "carpet"=>1, "as"=>1, "java"=>1, "javascript"=>1}
assert_equal counts, phrase.word_count
end
def test_include_numbers
skip
phrase = Phrase.new("testing, 1, 2 testing")
counts = {"testing"=>2, "1"=>1, "2"=>1}
assert_equal counts, phrase.word_count
end
def test_normalize_case
skip
phrase = Phrase.new("go Go GO Stop stop")
counts = {"go"=>3, "stop"=>2}
assert_equal counts, phrase.word_count
end
def test_with_apostrophes
skip
phrase = Phrase.new("First: don't laugh. Then: don't cry.")
counts = {"first"=>1, "don't"=>2, "laugh"=>1, "then"=>1, "cry"=>1}
assert_equal counts, phrase.word_count
end
def test_with_quotations
skip
phrase = Phrase.new("Joe can't tell between 'large' and large.")
counts = {"joe"=>1, "can't"=>1, "tell"=>1, "between"=>1, "large"=>2, "and"=>1}
assert_equal counts, phrase.word_count
end
# Problems in exercism evolve over time, as we find better ways to ask
# questions.
# The version number refers to the version of the problem you solved,
# not your solution.
#
# Define a constant named VERSION inside of the top level BookKeeping
# module, which may be placed near the end of your file.
#
# In your file, it will look like this:
#
# module BookKeeping
# VERSION = 1 # Where the version number matches the one in the test.
# end
#
# If you are curious, read more about constants on RubyDoc:
# http://ruby-doc.org/docs/ruby-doc-bundle/UsersGuide/rg/constants.html
def test_bookkeeping
skip
assert_equal 1, BookKeeping::VERSION
end
end
class Phrase
VERSION = 1
def initialize(phrase)
@phrase = phrase
end
def word_count
counts = {}
normalized_phrase = remove_punctuation(@phrase).downcase
normalized_phrase.split.each do |word|
counts[word] ||= 0
counts[word] += 1
end
counts
end
private
def remove_punctuation(phrase)
# apostrophes permitted only for abbreviations
phrase_without_apostrophes = remove_apostrophes_except_between_word_chars(phrase)
remove_punctuation_except_apostrophes(phrase_without_apostrophes)
end
def remove_apostrophes_except_between_word_chars(phrase)
phrase.gsub(/(?<=\W)'|'(?=\W)/, '')
end
def remove_punctuation_except_apostrophes(phrase)
phrase.gsub(/[^\w']/, ' ')
end
end
A huge amount can be learned from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.
Here are some questions to help you reflect on this solution and learn the most from it.
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Community comments
I have never seen a regular expression that I would consider readable, hence the long methods names to explain exactly what these regular expressions do.
I'd rather use comments instead of long method names to explain what the regular expression does :-)