[英]How to restructure results from database
I've got a model User which has id, name, surname, role_id, permission_id 我有一个模型User,它有id,name,surname,role_id,permission_id
Here is few user entries : 这里有一些用户条目:
User => {:name => 'Bob', :surname => 'surnmae', :role_id => 1, :permission_id = 2}
User => {:name => 'Alice', :surname => 'strange', :role_id => 1, :permission_id = 3}
User => {:name => 'Ted', :surname => 'Teddy', :role_id => 2, :permission_id = 3}
Now I need to group them first by role_id
and then by permission_id
, here is what I mean : 现在我需要先通过role_id
然后通过permission_id
对它们进行分组,这就是我的意思:
Category.select([:name, :role_id, :permission_id]).group_by(&:role_id) Category.select([:name,:role_id,:permission_id])。group_by(&:role_id)
Produces : 产品:
{1 =>
[#<User name: "Bob", role_id: 1, permission_id: 2>,
#<User name: "Alice", role_id: 1, permission_id: 3>]
2 => [#<User name: "Ted", role_id: 2, permission_id: 3>]
}
Which is close enough but I need them grouped with permission_id as well so it would look like this : 哪个足够接近,但我需要将它们与permission_id分组,所以它看起来像这样:
{:role_id => {:permision_id => [Array of users grouped by this criteria]}
}
maybe something like 也许是这样的
Category.select([:name, :role_id, :permission_id]).group_by(&:role_id).map{|role| Category.select([:name,:role_id,:permission_id])。group_by(&:role_id).map {| role | role.group_by(&:permission_id)} role.group_by(&:permission_id)}
It is bit more tricky than it seems. 它看起来有点棘手。 It is better to write it into multiple steps. 最好将其分为多个步骤。 However, the following one-liner will work: 但是,以下单行程将起作用:
Hash[ User.all.group_by(&:role_id).collect{|role, grp| [role, grp.group_by(&:permission_id)]} ]
Output will be the following (which is probably what you are looking for): 输出将是以下(这可能是您正在寻找的):
{1=>
{2=>[{:name=>"Bob", :surname=>"surnmae", :role_id=>1, :permission_id=>2}],
3=>[{:name=>"Alice", :surname=>"strange", :role_id=>1, :permission_id=>3}]},
2=>{3=>[{:name=>"Ted", :surname=>"Teddy", :role_id=>2, :permission_id=>3}]}}
Same logic, but simpler to comprehend: 相同的逻辑,但更容易理解:
output={}
User.all.group_by(&:role_id).each{|role, grp| output[role]= grp.group_by(&:permission_id)}
# output has required goruping
Category.select([:name, :role_id, :permission_id]).group_by { |category| [category.role_id, category.permission_id] }
编辑:没关系,这并不能提供您正在寻找的格式。
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