标签: ruby

如何使用Ruby 1.8.7在Array中找到值？

我有这个字符串:

"some text\nandsomemore"

我需要从中删除"\n".我试过了

"some text\nandsomemore".gsub('\n','')

但它不起作用.我该怎么做？谢谢阅读.

我想在ruby中编写一个简单的A + B程序,但我不知道如何使用控制台.

rails g model Rating user_id:integer message:string value:integer

我怎样才能完全删除这个模型？谢谢

我有这个:

hash  = { "a"=>["a", "b", "c"], "b"=>["b", "c"] } 

我想谈谈这个: [["a","b","c"],["b","c"]]

这似乎应该可以工作,但它不会:

hash.each{|key,value| value}
=> {"a"=>["a", "b", "c"], "b"=>["b", "c"]} 

有什么建议？

我想在Rails 4中禁用ActiveRecord.我做了以下内容 config/application.rb

require File.expand_path('../boot', __FILE__)

# require 'rails/all'  -- commented

require "action_controller/railtie"
require "action_mailer/railtie"
#require "active_resource/railtie" no need
#require "rails/test_unit/railtie" no need
#require "sprockets/railtie" no need

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(:default, Rails.env)

module MyApp
  class Application < Rails::Application
     config.app_middleware.delete "ActiveRecord::ConnectionAdapters::ConnectionManagement"
  end
end

我有一个错误

/home/alex/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/railtie/configuration.rb:95:in 
  method_missing: undefined method active_record for #<Rails::Application::Configuration:0x00000002005c38> (NoMethodError)

我正在开发一个从YouTube下载视频,将其转换为MP3并为文件创建目录结构的程序.

我的代码是:

FileUtils.cd("#{$musicdir}/#{$folder}") do
  YoutubeDlhelperLibs::Downloader.get($url)
  if File.exists?('*.mp4')
    puts 'Remove unneeded tempfile'
    Dir['*.mp4'].each do |waste|
      File.delete(waste)
    end
  else
    puts 'Temporary file already deleted'
  end

  Dir['*.m4a'].each do |rip|
    rip.to_s
    rip.split
    puts 'Inside the function'
    puts rip
  end

end

第一个进入已创建的音乐文件夹.在里面,我正在执行get.之后我在目录中有两个文件:"xyz.mp4"和"xyz.m4a".

我想获取没有扩展名的文件名,所以我可以用不同的方式处理这两个文件.

我正在使用一个数组,但只有一个匹配的数组对我来说听起来很疯狂.

有没有人有其他想法？

我在db中有一个datetime列,当我向用户显示时,我希望将其转换为一个简单的日期.

我怎样才能做到这一点？

def shown_date
  # to_date does not exist, but is what I am looking for
  self.date || self.exif_date_time_original.to_date 
end

我刚刚阅读了一篇博客文章,并注意到作者tap在一个片段中使用了类似于:

user = User.new.tap do |u|
  u.username = "foobar"
  u.save!
end

我的问题是使用的好处或优势究竟是什么tap？我不能这样做:

user = User.new
user.username = "foobar"
user.save!

或者更好的是:

user = User.create! username: "foobar"

在我的工作和家用计算机上,我最近使用了将Ruby升级到2.3.1 ruby-install.我chruby用作我的Ruby切换器.

我开始在终端看到这个警告:

Ignoring bcrypt-3.1.11 because its extensions are not built.  Try: gem pristine bcrypt --version 3.1.11
Ignoring bcrypt-3.1.10 because its extensions are not built.  Try: gem pristine bcrypt --version 3.1.10
Ignoring binding_of_caller-0.7.2 because its extensions are not built.  Try: gem pristine binding_of_caller --version 0.7.2
Ignoring byebug-9.0.5 because its extensions are not built.  Try: gem pristine byebug --version 9.0.5
Ignoring byebug-5.0.0 because its extensions are not built.  Try: gem pristine byebug --version 5.0.0
Ignoring concurrent-ruby-ext-1.0.2 because its …