红宝石：如何任一个变量设置为0，或者，如果它已被设置，递增1 [英] Ruby: How to either set a variable to 0 or, if it is already set, increment by 1

问题描述

我知道|| =操作，但不认为这会帮助我在这里...试图创建计算对象的数组中类型的数量的数组。

  array.each做| C |
  newarray [c.type] = newarray [c.type] newarray [c.type] +1？ 0
结束
 

有没有更优雅的方式来做到这一点？

解决方案

  =类型Hash.new（-1）＃这感觉就像这应该是0，但要
                     ＃等同于你的榜样，它必须是-1
array.each做| C |
  类型[c.type] + = 1
结束
 

I know of the ||= operator, but don't think it'll help me here...trying to create an array that counts the number of "types" among an array of objects.

array.each do |c|
  newarray[c.type] = newarray[c.type] ? newarray[c.type]+1 ? 0
end

Is there a more graceful way to do this?

解决方案

types = Hash.new(-1) # It feels like this should be 0, but to be
                     # equivalent to your example it needs to be -1
array.each do |c|
  types[c.type] += 1
end

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