Question

我有一段代码，可以在一段时间内获取签到列表。请参阅下面的代码。

from = Time.zone.now.beginning_of_month
to   = Time.zone.now.end_of_month
customer_checkins = CustomerCheckin.where(account_id: seld.id, created_at: from..to)

然后代码会给我所有符合给定条件的签到对象。我需要做的下一件事是将每个客户的签到列表分组。所以我有这个代码来做到这一点。

group_customer_id = customer_checkins.group(:customer_id).count

按客户ID对其进行分组将导致哈希。见下面的例子。

{174621 =＆GT; 9,180262 =＆GT; 1,180263 =＆GT; 1,180272 =＆GT; 1,180273 =＆GT; 3,180274 =＆GT; 3,180275 =＆GT; 4,180276 =＆GT; 3,180277 =＆GT; 2,180278 =＆GT; 4,180279 =＆GT; 4,180280 =＆GT; 3,180281 =＆GT; 5,180282 =＆GT; 8}

我现在想要获得具有相同签到数量的客户数量 - 有多少客户有9个签到，5个签到等等。所以给出上面的哈希。我期待这样的输出：

{9 =＆gt; 1,8 =＆gt; 1,5 =＆gt; 1,4 =＆gt; 3,3 =＆gt; 4,2 =＆gt; 1,1 =＆gt; 3}

Answer 1

h.each_with_object({}) {|(k,v), h| h[v] = h[v].to_i + 1}
# => {9=>1, 1=>3, 3=>4, 4=>3, 2=>1, 5=>1, 8=>1}

Answer 2

从哈希中获取值：

customer_array = {174621=>9,180262=>1,180263=>1,180272=>1,180273=>3,180274=>3,180275=>4,180276=>3,180277=>2,180278=>4,180279=>4,180280=>3,180281=>5,180282=>8}.values
customer_count = Hash.new(0)

customer_array.each do |v|
  customer_count[v] += 1
end

puts customer_count

Answer 3

a = {174621=>9,180262=>1,180263=>1,180272=>1,180273=>3,180274=>3,180275=>4,180276=>3,180277=>2,180278=>4,180279=>4,180280=>3,180281=>5,180282=>8}

result = a.map{|k,v| v}.each_with_object(Hash.new(0)) { |word,counts| counts[word] += 1 }

# => {9=>1, 1=>3, 3=>4, 4=>3, 2=>1, 5=>1, 8=>1}

按值对哈希进行分组，并获取Rails中一个组下的值的计数

3 个答案: