标签: ruby

我有一个活动,start_time并且end_time想要检查活动是否"正在进行中".那将是检查今天的日期是否在两个日期之间的范围内.

你会如何在一个函数中做到这一点？

return和变换之间有什么区别,如下所示:

没有回报

def write_code(number_of_errors)
  if number_of_errors > 1
     mood = "Ask me later"
  else
     mood = "No Problem"
  end  
  mood
end

返回

def write_code(number_of_errors)
  if number_of_errors > 1
    mood =  "Ask me later"
  else
    mood = puts "No Problem"
  end  
  return mood
end

我希望这是一个简单的问题.在下面的示例中,如何检查是否已定义常量？

#this works
var = var||1
puts var
var = var||2
puts var

#this doesn't
CONST = CONST||1
puts CONST
CONST = CONST||2
puts CONST

=> 1
   1
   uninitialized constant CONST (NameError)

如果实例变量属于某个类,我可以@hello直接使用类实例访问实例变量(例如)吗？

class Hello
  def method1
    @hello = "pavan"
  end
end

h = Hello.new
puts h.method1

我正在使用IRB(交互式ruby控制台)来学习如何使用Ruby编程.如果我先在文本编辑器中编写程序,如何将文件加载到控制台？

我有两个任务数组 - 创建和分配.我想从创建的任务数组中删除所有已分配的任务.这是我工作但很乱的代码:

    @assigned_tasks = @user.assigned_tasks
    @created_tasks = @user.created_tasks

    #Do not show created tasks assigned to self
    @created_not_doing_tasks = Array.new
    @created_tasks.each do |task|
        unless @assigned_tasks.include?(task)
            @created_not_doing_tasks << task
        end
    end

我相信有更好的方法.它是什么？谢谢 :-)

所以有

record.new_record?

检查某些东西是否是新的

我需要检查是否有东西出来了.

record = some_magic
record.destroy
record.is_destroyed? # => true

这样的事情.我知道毁灭会冻结物体,所以冻结？有点作品,但这个任务有明确的东西吗？

我正在使用Ruby on Rails 3.0.9,我想检查一个数字是否包含在一个范围内.也就是说,如果我有一个变量,number = 5我想检查1 <= number <= 10并检索一个布尔值,如果该number值包含在该范围内.

我可以这样做:

number >= 1 && number <= 10

但我想在一个声明中这样做.我怎样才能做到这一点？

我postgresql-9.2.4从源代码安装,现在在执行时使用rails app:

rake db:create 命令我得到:

$ bin/rake db:create RAILS_ENV="test"
PG::Error: ERROR:  new encoding (UTF8) is incompatible with the encoding of the template database (SQL_ASCII)
HINT:  Use the same encoding as in the template database, or use template0 as template.
: CREATE DATABASE "verticals_test" ENCODING = 'unicode'
/home/vagrant/my-project/.gems/ruby/1.9.1/gems/activerecord-3.2.12/lib/active_record/connection_adapters/postgresql_adapter.rb:652:in `exec
....
bin/rake:16:in `load'
bin/rake:16:in `<main>'
Couldn't create database for {"adapter"=>"postgresql", "encoding"=>"unicode", "database"=>"my_db", "host"=>"localhost", "pool"=>5, "username"=>"my_user", "password"=>"my_password"}

任何的想法？

我尝试运行我rails c但由于某种原因,我收到此错误:

https://gist.github.com/anonymous/166713e8cde860fb188a8dffb98a1563

? rails c
Running via Spring preloader in process 6609
/Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require': dlopen(/Users/zulhilmi/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/x86_64-darwin15/readline.bundle, 9): Library not loaded: /usr/local/opt/readline/lib/libreadline.6.dylib (LoadError)
  Referenced from: /Users/zulhilmi/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/x86_64-darwin15/readline.bundle
  Reason: image not found - /Users/zulhilmi/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/x86_64-darwin15/readline.bundle
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `block in require'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /Users/zulhilmi/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/irb/completion.rb:10:in `<top (required)>'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `block in require'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/railties-4.2.6/lib/rails/commands/console.rb:3:in `<top (required)>'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `block in require'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
    from /Users/zulhilmi/.rvm/gems/ruby-2.3.1@useradmin/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require' …