Lambda和->之间的区别Ruby中的运算符 [英] Difference between lambda and -> operator in Ruby

问题描述

以下两个作用域产生相同的结果，哪种语法更可取，还有其他区别吗?

The following two scopes generate the same result, which syntax is preferable and is there any other difference?

scope :paid, lambda { |state| where(state: state) }

scope :paid, ->(state) { where(state: state) }

推荐答案

由于可读性原因，最好对单行代码使用新语法->(在Ruby 1.9中引入)，对多行代码使用lambda线块.示例:

It's preferable, due to readibility reasons, to use new syntax -> (introduced in Ruby 1.9) for single-line blocks and lambda for multi-line blocks. Example:

# single-line
l = ->(a, b) { a + b }
l.call(1, 2)

# multi-line
l = lambda do |a, b|
  tmp = a * 3
  tmp * b / 2
end
l.call(1, 2)

似乎在 bbatsov/ruby​​-style-guide中建立的社区约定.

因此，根据您的情况，会更好:

So, in your case, would be better:

scope :paid, ->(state) { where(state: state) }

这篇关于Lambda和->之间的区别Ruby中的运算符的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！