Arel:如何使用 OR 干净地连接多个条件? [英] Arel: How to cleanly join multiple conditions with OR?

问题描述

在我的 Rails 应用程序中，我遍历一个数组以创建一个必须由 OR 连接的条件列表.以下是我目前的基本流程.

In my Rails app, I loop through an array to create a list of conditions that must be joined by OR. Below is the basic flow of how I currently do so.

conditions = nil
set.each do |value|
  condition = value.to_condition
  conditions = conditions ? conditions.or(condition) : condition
end

显然，它并不漂亮，但我仍然不完全了解 Arel.它是否提供了对一组动态生成的条件进行 OR-join 的更好方法?

Obviously, it's not beautiful, but I still don't fully know my way around Arel. Does it offer any better way of OR-joining a set of dynamically-generated conditions?

推荐答案

这非常适合 inject ，它会给你一个单行代码，你也可以在其他东西中使用:conditions = set.inject { |conds, cond|conds.or(cond) } 甚至可以写成: set.inject(&:or) 非常好.

This is a perfect fit for an inject which will give you a one-liner you can use within something else as well: conditions = set.inject { |conds, cond| conds.or(cond) } which can even be written: set.inject(&:or) which is very nice.

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