Ruby on Rails 开关 [英] Ruby on Rails Switch

问题描述

谁能提供一个示例，说明如何在 Ruby 中为变量使用 switch case?

Can someone provide an example on how to use switch case in Ruby for variable?

推荐答案

我假设你指的是 case/when.

I assume you refer to case/when.

case a_variable # a_variable is the variable we want to compare
when 1    #compare to 1
  puts "it was 1" 
when 2    #compare to 2
  puts "it was 2"
else
  puts "it was something else"
end

或

puts case a_variable
when 1
  "it was 1"
when 2
  "it was 2"
else
  "it was something else"
end

编辑

可能不是每个人都知道但非常有用的是，您可以在 case 语句中使用正则表达式.

Something that maybe not everyone knows about but what can be very useful is that you can use regexps in a case statement.

foo = "1Aheppsdf"

what = case foo
when /^[0-9]/
  "Begins with a number"
when /^[a-zA-Z]/
  "Begins with a letter"
else
  "Begins with something else"
end
puts "String: #{what}"

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