我假设您的表按照Rails约定是单个相册。

I'm assuming your table is singular Album per Rails convention. If not, consider changing it.

 Album.all.map { |album| [Date::MONTHNAMES[album.date.month], album.date.year].join(' ') }
  .each_with_object(Hash.new(0)) { |month_year, counts| counts[month_year] += 1 }

说明：

.map 方法遍历相册并返回由 [ month year， month year， ...] 。

The .map method iterates over the albums and returns an array of strings consisting of ["month year", "month year", ... ].

.each_with_object 方法是一种标准计数算法，可为每个唯一数组项返回带有计数的哈希。

The .each_with_object method is a standard counting algorithm that returns a hash with a count for each unique array item.