Ruby Notes

While reading RubyMonk tutorials

1. Truthiness of objects in Ruby
Only objects false and nil equates to false. Every other object like say 1, 0, "" are all evaluated to be true.

2. Use break in infinite loops

loop do
  monk.meditate
  break if monk.nirvana?
end

3. Append to an array, use << operator

[1, 2, 3, 4, 5] << 'woot'
[1, 2, 3, 4, 5, "woot"]

4. Filter elements of an array, use 'select'

names = ['rock', 'paper', 'scissors', 'lizard', 'spock']
names.select { |word| word.length > 5 }

5. Delete elements of an array, use 'delete_if'

[1,2,3,4,5,6,7,8,9].delete_if { |i| i % 2 == 0 }

6. Methods are themselves objects, and responds using 'call'

next_method_object = 1.method("next")
puts next_method_object.call

7. Beware of shallow object copies, to do a deep copy use Marshal

new_job = Marshal.load(Marshal.dump(job))

8. Use heredoc for convenient multiline strings. The dash ignores spaces before placeholder. The gsub takes care of removing spaces at beginning of each line.

def long_message
  puts <<-EOT.gsub(/^\s*/, '')
    Here goes a very long message...
    Sincerely,
    Dr. Foobear
  EOT
end

7. Use 'send' when testing private methods

# obj.send(:method_name, args)
@parser.send(:running?, test_strings)