_random-ruby-tips.md

rAndom ruBy tiPs >>--(o_0)-->

do-end-vs-bracket.md

do..end vs bracket {}

Bracket syntax {} has higher precedence than do..end syntax [1]

[1] http://stackoverflow.com/questions/2122380/using-do-block-vs-brackets

# In this case
def outer(foo)
  puts "foo: #{foo.inspect}"
  yield if block_given?
end

# Use {} OK!
outer [1,2,3].map {|n| n.to_i+1}
# foo: [2, 3, 4]
# => nil
 
# Use do..end KO!
outer [1,2,3].map do |n|
  n.to_i+1
end
# foo: #<Enumerator: [1, 2, 3]:map>
# => 1

map-hash-values.md

hash.merge(hash){|_,v,_| v*2}

remove-database-yml.md

Remove database.yml

In Rails 4, you can remove config/database.yml if you provide ENV['DATABASE_URL'].

ActiveRecord, rails server and rake db:* all work as expected.

Except rake dbconsole, it breaks now, but a pull request is submitted [1].

[1] rails/rails#13328

Try this runnable example:

http://runnable.com/UqwTZZACPDwtAAEj/rails-4-runs-well-without-database-yml-for-12factor

triple-equals.md

String === "foo"  # true
"foo" === String  # false
->(x) { x == 2 } === 2  # true