为什么这个.each块不会像.select一样返回？

Question

从CodeQuizzes＃6：从captain_planet数组创建一个新数组，其中包含所有包含字母“a”的元素。

captain_planet = ["earth", "fire", "wind", "water", "heart"]

我理解他们的回答：

captain_planet.select do |word|
  word.include?("a")
end

但是，我似乎无法弄清楚为什么这不会返回同样的事情：

ret = []

captain_planet.each do |x|
    if x.include?('a')
        ret.push(x)
    end
end

思想？

Answer 1

尝试在块结束后查看ret的输出。

2.0.0p247 :001 > ret = []
 => []
2.0.0p247 :002 > captain_planet = ["earth", "fire", "wind", "water", "heart"]
 => ["earth", "fire", "wind", "water", "heart"]
2.0.0p247 :003 > captain_planet.each do |x|
2.0.0p247 :004 >         if x.include?('a')
2.0.0p247 :005?>             ret.push(x)
2.0.0p247 :006?>         end
2.0.0p247 :007?>   end
 => ["earth", "fire", "wind", "water", "heart"]
2.0.0p247 :008 > puts ret
earth
water
heart
 => nil