In condition,
COLUMN = [:id, :tag_list, :price, :url, :Perweight, :Totalweight, :memo, :created_at, :updated_at]
row = {"id"=>4, "tag_list"=>"peanuts", "price"=>100, "Totalweight"=>390, "Perweight"=>nil, "url"=>nil, "memo"=>nil, nil=>nil}
from these two conditions, I want to make above Hash Object.
{:id=>4, :tag_list=>"peanuts", :price=>100, :Totalweight"=>390, :Perweight=>nil, :url=>nil, memo=>nil}
I tried, like this...
at first, I make empty hash,
new = Hash[COLUMN.zip([])]
p new
--->
{:id=>nil, :tag_list=>nil, :price=>nil, :url=>nil, :Perweight=>nil, :Totalweight=>nil, :memo=>nil, :created_at=>nil, :updated_at=>nil}
and then, I dont know how to do that,
Please give me advice?
You can use Symbolize Keys.
row.symbolize_keys
or destructively
row.symbolize_keys!
Related
I have the following params:
params={"data"=>
{"type"=>"book",
"id"=>14,
"attributes"=>
{"id"=>14,
"created_at"=>"2022-06-27 21:15:39",
"title"=>"sdfdsf",
"targeting"=> { "release_times"=>[["4:00", "5:00"], ["5:00", "6:00"]],
"days"=>["Monday", "Tuesday", "Wednesday"],
"gender"=>["male", "female"]
}
}
}
When I use this, I can get every value but release_times is always null:
When I use this:
safe_params = params.require(:data).permit( attributes: [:id, :created_at, :title, { targeting: {} }])
How can I extract the release times value?
I tried doing this
safe_params = params.require(:data).permit( attributes: [:id, :created_at, :title, { targeting: [:days, :gender, release_times:[]]}])
But I get the error:
Validation failed: Targeting gender should be a list of values, Targeting days should be a list of values
How can I extract all the values from targeting including the release_times?
As Ruby on Rails API states, when using ActionController::Parameters you want to declare that a parameter should be an array (list) by mapping it to a empty array. Like you did with release_times.
You should permit targeting params with [days: [], gender: []] instead of [:days, :gender]. This should solve the error.
But even them, release_times is an array of arrays, which I believe is not supported at the moment (there is an old issue for it).
One way you could bypass this would be by changing the way you're communicating release_times. Using an arrays of hashes instead of nested arrays.
From this:
"release_times"=>[["4:00", "5:00"], ["5:00", "6:00"]]
To this (or something similar):
"release_times"=>[{"start" => "4:00", "end"=>"5:00"}, {"start" =>"5:00", "end" => "6:00"}]
That way, you could do this:
safe_params = params.require(:data).permit(attributes: [:id, :created_at, :title, { targeting: [days: [], gender: [], release_times: [:start, :end]] }])
Exactly how you would implement that is up to you, but I hope it helps.
**Also, there was a typo with release_times.
You can do some testing yourself. Open rails c and do something like this:
param = ActionController::Parameters.new("targeting"=> { "release_times"=>[["4:00", "5:00"], ["5:00", "6:00"]]})
param.require(:targeting).permit(release_times: []) # > Doesn't return times.
new_param = ActionController::Parameters.new("targeting"=> { "release_times"=>[{"start" => "4:00", "end"=>"5:00"}, {"start" =>"5:00", "end" => "6:00"}] })
new_param.require(:targeting).permit(release_times: [:start, :end]) # > Return times.
Just an observation, using permit! would work. But as strong params doc says:
Extreme care should be taken when using permit! as it will allow all
current and future model attributes to be mass-assigned.
So you could try to slice arguments yourself and them permit! - but I can't tell you that's the way to go.
Learn more about Mass Assignment Vulnerability here.
How to permit this parameters:
contacts: [
{:value => 'value', :contacts_type => 'contact_type'},
{:value => 'value', :contacts_type => 'contact_type'},
]
To create many objects by controller action in one JSON request?
Like below, contacts will be an array of resources with specific attributes value and contacts_type:
params.permit(contacts: [:value, :contacts_type])
If you get params like the following:--
:params=>{:xyz => {:contacts => [{:value => 'value', :contacts_type => 'type'}, ..]}}
Then do the folowing:--
params.require(:xyz).permit(contacts: [:value, :contacts_type])
And add attr_accessor :contacts to your model if contacts is just a form field name part.
Work around for this should be
def contact_params
new_params = params.permit(contacts: [:value, :contacts_type])
new_params[:contacts] if new_params
end
Please suggest alternate solution if any
I have a place object that has the following parameters: phone, category, street, zip, website.
I also have an array of place objects: [place1, place2, place3, place4, place5].
What's the best way to sort the array of places, based on the parameter availability? I.e., if place1 has the most available parameters, or the least number of parameters that are nil, it should be reordered to first and so on.
Edit: These objects are not ActiveRecord objects
I'd let each Place object know how complete it was:
class Place
attr_accessor :phone, :category, :street, :website, :zip
def completeness
attributes.count{|_,value| value.present?}
end
end
Then it is easy to sort your place objects by completeness:
places.sort_by(&:completeness)
Edit: Non-ActiveRecord solution:
I had assumed this was an ActiveRecord model because of the Ruby on Rails tag. Since this is a non-ActiveRecord model, you can use instance_variables instead of attributes. (By the way, congratulations for knowing that domain models in Rails don't have to inherit from ActiveRecord)
class Place
attr_accessor :phone, :category, :street, :website, :zip
def completeness
instance_variables.count{|v| instance_variable_get(v).present?}
end
end
Edit 2: Weighted attributes
You have a comment about calculating a weighted score. In this case, or when you want to choose specific attributes, you can put the following in your model:
ATTR_WEIGHTS = {phone:1, category:1, street:2, website:1, zip:2}
def completeness
ATTR_WEIGHTS.select{|k,v| instance_variable_get(k).present?}.sum(&:last)
end
Note that the sum(&:last) is equivalent to sum{|k,v| v} which in turn is a railsism for reduce(0){|sum, (k,v)| sum += v}.
I'm sure there's a better way to do it, but this is a start :
ruby fat one liner
values = {phone: 5, category: 3, street: 5, website: 3, zip: 5} #Edit these values to ponderate.
array = [place1, place2, place3, place4, place5]
sorted_array = array.sort_by{ |b| b.attributes.select{ |k, v| values.keys.include?(k.to_sym) && v.present? }.inject(0){ |sum, n| sum + values[n[0]] } }.reverse
So we're basically creating a sub-hash of the attributes of your ActiveRecord object by only picking the key-value pairs that are in the values hash and only if they have a present? value.
Then on this sub-hash, we're invoking inject that will sum the ponderated values we've put in the values hash. Finally, we reverse everything so you have the highest score first.
To make it clean, I suggest you implement a method that will compute the score of each object in an instance method in your model, like mark suggested
If you have a class Place:
class Place
attr_accessor :phone, :category, :street, :website, :zip
end
and you create an instance place1:
place1 = Place.new
place1.instance_variables # => []
place1.instance_variables.size # => 0
place1.phone = '555-1212' # => "555-1212"
place1.instance_variables # => [ :#phone ]
place1.instance_variables.size # => 1
And create the next instance:
place2 = Place.new
place2.phone = '555-1212'
place2.zip = '00000'
place2.instance_variables # => [ :#phone, :#zip ]
place2.instance_variables.size # => 2
You can sort by an ascending number of instance variables that have been set:
[place1, place2].sort_by{ |p| p.instance_variables.size }
# => [ #<Place:0x007fa8a32b51a8 #phone="555-1212">, #<Place:0x007fa8a31f5380 #phone="555-1212", #zip="00000"> ]
Or sort in descending order:
[place1, place2].sort_by{ |p| p.instance_variables.size }.reverse
# => [ #<Place:0x007fa8a31f5380 #phone="555-1212", #zip="00000">, #<Place:0x007fa8a32b51a8 #phone="555-1212"> ]
This uses basic Ruby objects, Rails is not needed, and it asks the object instances themselves what is set, so you don't have to maintain any external lists of attributes.
Note: this breaks if you set an instance variable to something, then set it back to nil.
This fixes it:
[place1,place2].sort_by{ |p|
p.instance_variables.reject{ |v|
p.instance_variable_get(v).nil?
}.size
}.reverse
and this shortens it by using Enumerable's count with a block:
[place1,place2].sort_by{ |p|
p.instance_variables.count{ |v|
!p.instance_variable_get(v).nil?
}
}.reverse
I have a class Sample
Sample.class returns
(id :integer, name :String, date :date)
and A hash has all the given attributes as its keys.
Then how can I initialize a variable of Sample without assigning each attribute independently.
Something like
Sample x = Sample.new
x.(attr) = Hash[attr]
How can I iterate through the attributes, the problem is Hash contains keys which are not part of the class attributes too
class Sample
attr_accessor :id, :name, :date
end
h = {:id => 1, :name => 'foo', :date => 'today', :extra1 => '', :extra2 => ''}
init_hash = h.select{|k,v| Sample.method_defined? "#{k}=" }
# This will work
s = Sample.new
init_hash.each{|k,v| s.send("#{k}=", v)}
# This may work if constructor takes a hash of attributes
s = Sample.new(init_hash)
Take a look at this article on Object initialization. You want an initialize method.
EDIT You might also take a look at this SO post on setting instance variables, which I think is exactly what you're trying to do.
Try this:
class A
attr_accessor :x, :y, :z
end
a = A.new
my_hash = {:x => 1, :y => 2, :z => 3, :nono => 5}
If you do not have the list of attributes that can be assigned from the hash, you can do this:
my_attributes = (a.methods & my_hash.keys)
Use a.instance_variable_set(:#x = 1) syntax to assign values:
my_attributes.each do |attr|
a.instance_variable_set("##{attr.to_s}".to_sym, my_hash[attr])
end
Note(Thanks to Abe): This assumes that either all attributes to be updated have getters and setters, or that any attribute which has getter only, does not have a key in my_hash.
Good luck!
I have a collection of model objects that I am trying to return JSON for. E.G
#regions.to_json(:only => [:id, :name ])
that works fine.
If I try to use :
#regions.to_json(:only => [:friendly_id, :name ])
then nothing is returned for the friendly_id. The model does have:
has_friendly_id :name, :use_slug => true
So I am wondering what I am missing - or if I am not allowed to use
friendly_id's in to_json?
Try using
#regions.to_json(:only => [:id, :cached_slug])