Type inference is the new hotness. Let’s (auto)-convert a list of strings into properly typed values.
The challenge: Code a convert method that passes the RubyQuizTest :-).
def convert( values )
# ...
end
For the starter level 1 turn a random list of strings:
["2018", "2018.12", "2018.12.25", "25 Gems", "NaN", "1820", "18.20", "Nil", "Null"]
into a properly typed list of values:
[2018, 2018.12, Date.new(2018,12,25), "25 Gems", Float::NAN, 1820, 18.2, nil, nil]
# => [2018, 2018.12, #<Date: 2018-12-25>, "25 Gems", NaN, 1820, 18.2, nil, nil]
Note: NaN is short for Not a Number (that is, Float::NAN).
To pass the RubyQuizTest all type classes must match too, that is:
[Integer, Float, Date, String, Float, Integer, Float, NilClass, NilClass]
To make sure the order in the list doesn’t matter, that is, integer before float numbers or float before integer numbers or date before integer numbers and so on - convert gets called five times with a shuffled sample with a different “randomized” order every time.
Start from scratch or, yes, use any library / gem you can find.
To qualify for solving the code challenge / puzzle you must pass the test:
require 'minitest/autorun'
require 'date'
class RubyQuizTest < MiniTest::Test
def test_convert
pairs = [
["2018", 2018],
["2018.12", 2018.12],
["2018.12.25", Date.new(2018,12,25)],
["25 Gems", "25 Gems"],
["NaN", Float::NAN],
["1820", 1820],
["18.20", 18.2],
["Nil", nil],
["Null", nil]]
5.times do
values, exp_values = pairs.shuffle.reduce( [[],[]]) { |acc,pair| acc[0] << pair[0]; acc[1] << pair[1]; acc }
assert_equal exp_values, convert( values )
assert_equal exp_values.map { |v| v.class }, convert( values ).map { |v| v.class }
end
end # method test_convert
end # class RubyQuizTest
Post your code snippets on the “official” Ruby Quiz Channel, that is, the ruby-talk mailing list.
Happy data wrangling and type inferencing with Ruby.