ruby-on-rails - 用 Ruby 连接一系列单词/短语

Question

irb(main):001:0> a =  ["global climate change", "calamity", "glaciers", "new york times"]
  => ["global climate change", "calamity", "glaciers", "new york times"]
irb(main):002:0> a.join(', ')
  => "global climate change, calamity, glaciers, new york times"

我需要结果是

  => "global climate change", "calamity", "glaciers", "new york times"

想法？单线将是理想的。

Answer 1

通过 ActiveRecord 将选项数组传递给查询的正确方法是使用查询参数：

a = ["global climate change", "calamity", "glaciers", "new york times"]
Category.where("name IN (?)", a)
# Generated query:
# Category Load (0.4ms)  SELECT `categories`.* FROM `categories` WHERE (name in ('global climate change','calamity','glaciers','new york times'))

您无需执行任何特殊操作即可将其转换为有效的 SQL 片段。您应该特别避免将字符串格式化为 SQL 片段，因为如果不仔细清理，您可能会在应用程序中打开 SQL 注入漏洞。

Answer 2

在查询中使用数组非常简单：

arr = ["global climate change", "calamity", "glaciers", "new york times"]
Category.where(:name => arr)

绝对不需要生成一些奇怪的字符串；）

Answer 3

a =  ["global climate change", "calamity", "glaciers", "new york times"]
=> ["global climate change", "calamity", "glaciers", "new york times"]
%Q!"#{a.join('", "')}"!
=> "\"global climate change\", \"calamity\", \"glaciers\", \"new york times\""
a.map{|e| "\"#{e}\""}.join(', ')
=> "\"global climate change\", \"calamity\", \"glaciers\", \"new york times\""

Answer 4

array = ['bob', 'bill']
new_array_string = array.map { |name| "'#{name}'" }.join(',')
=> "'bob', 'bill'"
User.where("name IN (#{new_array_string})")