rayway30419

# config/initializers/aws-sdk.rb
# configure your credential at ~/.aws/credential
# [kdan]
# aws_access_key_id=your_access_key_id
# aws_secret_access_key=your_secret_access_key
if File.exist? File.expand_path('~/.aws/credentials')
  Aws.config.update(
    credentials: Aws::SharedCredentials.new(profile_name: 'kdan'),
  )
end

rayway30419

module A
  def init_ddb_client
    Aws::DynamoDB::Client.new
  end

  def query params
    client = init_ddb_client # Exception here
    # loop for counting
  end
end

rayway30419

# Ruby內除了nil以及false以外皆為真值
obj = 0 
obj = ''
obj = {}
puts obj ? true : false
# true

rayway30419

videos = Hash.new do |h,k|
  h[k] = "https://www.youtube.com/watch?v=#{k.to_s}" 
end
%w(vVyf_TqWVzI cZFPVAOrdXQ 5tQ4xHMR3iU).each { |id| videos[id] }
puts videos
# {
#   "vVyf_TqWVzI"=>"https://www.youtube.com/watch?v=vVyf_TqWVzI",
#   "cZFPVAOrdXQ"=>"https://www.youtube.com/watch?v=cZFPVAOrdXQ",
#   "5tQ4xHMR3iU"=>"https://www.youtube.com/watch?v=5tQ4xHMR3iU"
# }

rayway30419

deep_hash = Hash.new { |h,k| h[k] = Hash.new(&h.default_proc) }
deep_hash[:a][:b][:c][:d] = 'Hello World'
puts deep_hash
# {:a=>{:b=>{:c=>{:d=>"Hello World"}}}}