如何使用红宝石”情况...当“不平等？

Question

你能在红宝石中做到这一点吗？ 它似乎“错过”了不平等的情况

 case myvar
 when  myvar < -5
    do somethingA
 when -5..-3
    do special_something_XX
 when -2..-1
    do special_something_YY
 when myvar == 0
    do somethingB
 when myvar > 0
    go somethingC
 end

Answer 1

您正在混合两种不同类型的 case 语句：

case var
when 1
  dosomething
when 2..3
  doSomethingElse
end

case
when var == 1
   doSomething
when var < 12
   doSomethingElse
end

Answer 2

   case myvar
     when  proc { |n| n < -5 }
        do somethingA
     when -5..-3
        do special_something_XX
     when -2..-1
        do special_something_YY
     when proc { |n| n == 0 }
        do somethingB
     when proc { |n| n > 0 }
        go somethingC
     end
   end

Answer 3

我个人并不认为使用 if 语句会更好，但如果您想要这种形式的解决方案：

Inf = 1.0/0

case myvar
when -Inf..-5
  do somethingA
when -5..-3
  do special_something_XX
when -2..-1
  do special_something_YY
when 0
  do somethingB
when 0..Inf
  do somethingC
end

我的首选解决方案如下。这里顺序很重要，你必须重复 myvar，但是遗漏情况要困难得多，你不必重复每个边界两次，而且严格性 (< code> 与 <= 而不是 .. 与 ... 相比）更为明显。

if myvar <= -5
  # less than -5
elsif myvar <= -3
  # between -5 and -3
elsif myvar <= -1
  # between -3 and -1
elsif myvar <= 0
  # between -1 and 0
else
  # larger than 0
end

Answer 4

def project_completion(percent)
 case percent
  when  percent..25
    "danger"
  when percent..50
    "warning"
  when percent..75
    "info"
  when percent..100
    "success"
  else
   "info"
  end
end

Answer 5

使用 infinity 可能会有所帮助

case var
when -Float::INFINITY..-1
when 0
when 1..2
when 3..Float::INFINITY
end