Rubyとblock

Transcript

1. Ruby&block
2. block do…end {…}
3. yield def foo yield end foo do puts "Hello!" end #=> Hello!
4. yield def foo yield if block_given? end foo do puts "Hello!" end #=> Hello! ! foo #=>
5. proc def foo &proc proc.call end proc = Proc.new do puts "Hello!" end foo &proc #=> Hello!
6. proc def foo name, &proc proc.call(name) end proc = Proc.new do |name| puts “Hello, #{name}!” end foo “Ruby”, &proc #=> Hello, Ruby!
7. lambda def foo &lambda lambda.call end lambda = -> {puts “Hello!”} foo &lambda #=> Hello!
8. proc ͱ lambda def foo block block.call 1, 2 end foo proc { |x, y, z| p x #=> 1 p y #=> 2 p z # => nil } def foo block block.call 1, 2 end foo lambda { |x, y, z| p x p y p z } # ArgumentError
9. Rails model class User < ActiveRecord::Base def admin? end end admin = [] User.all.each do |user| admin << user if user.admin? end User.select {|user| user.admin?} User.select(&:admin?)
10. Rails model scope class User < ActiveRecord::Base AUTHORITY_ADMIN = “admin” scope :admin, -> { where(authority: AUTHORITY_ADMIN) } ! def admin? end end
11. I can have fun coding in in Ruby
12. Thanks :)