I have an array (coming from a file_field, :multiple => true) in my params that I want to turn into a hash so I can build associated models for each element and process in my create action.
Currently receiving:
{"gallery"=>{"name"=>"A Gallery", "photos_attributes"=>{"0"=>{"image"=>[#<1st Image data removed for brevity>, #<2nd Image data removed for brevity>]}}}, "commit"=>"Save"}
I'd like to turn it into something like:
{"gallery"=>{"name"=>"A Gallery", "photos_attributes"=>{"0"=>{"image"=>#<1st Image data removed for brevity>}, "1"=>{"image"=>#<1st Image data removed for brevity>}}}, "commit"=>"Save"}
considered something like this but it's clearly wrong:
i = 0
params[:gallery][:photos_attributes]["0"][:image].reduce({}) do |result, element|
result[i++.to_s] = element
end
What's the "Rail's Way"?
You need to return the result hash at the end of each iteration.
i = 0
params[:gallery][:photos_attributes]["0"][:image].reduce({}) do |result, element|
result[(i += 1).to_s] = element
result
end
I've done something similar when receiving data from an iOS device. But, if I understand what you want and what your model(s) look like, to get nested attributes to work you don't want it to look like:
{ "photos_attributes" => { "0" => <image1>, "1" => <image2>, ... }
You want it to look like:
{ "photos_attributes" => [ <image1>, <image2>, ... ] }
And to do that all you need to do is:
params["gallery"]["photos_attributes"] = params["gallery"]["photos_attributes"]["0"]["image"]
Now, if I've misunderstood what you need, to get what you've asked for what you have might work (I don't use much reduce aka inject) or you could use tap:
i = 0
params["gallery"]["photos_attributes"] = {}.tap do |hash|
params["gallery"]["photos_attributes"]["0"]["image"].each do |image|
hash[i.to_s] = image
i = i + 1
end
end
Not a whole lot better IMO.
Related
I have a concept called snapshot which basically stores a snapshot of how data looked at a certain period of time. What I'm building is a method that loops through the snapshots for each events, and builds a small hash outlining the ownership over time for a given shareholder.
def fetch_ownership_over_time(shareholder, captable)
#shareholder = Shareholder.find(shareholder.id)
#captable = Captable.find(captable.id)
#company = #captable.company.id
#ownership_over_time = []
#captable.events.collect(&:snapshot).each do |snapshot|
parsed_snapshot = JSON.parse(snapshot)
#ownership_over_time.push(parsed_snapshot["event"]["name"])
#ownership_over_time.push(parsed_snapshot["event"]["date"])
parsed_snapshot["shareholders"].each do |shareholder|
if shareholder["id"] == #shareholder.id
#ownership_over_time.push(shareholder["ownership_percentage"])
end
end
end
return #ownership_over_time
end
I then call this method in my view which successfully retrieves the correct values however they are not structured in any way:
["Event 1 ", "2018-11-19", "0.666666666666667", "Event 2 ", "2018-11-19", "0.333333333333333", "4th event ", "2018-11-19", "0.315789473684211"]
What I'd like to do now though is construct my hash so that each separate snapshot event contains a name, date and ownership_percentage.
Perhaps something like this:
ownership_over_time = [
{
event_name = "Event 1" #parsed_snapshot["event"]["name"]
event_date = "20180202" #parsed_snapshot["event"]["date"]
ownership_percentage = 0.37 #shareholder["ownership_percentage"]
},
{
event_name = "Event 2" #parsed_snapshot["event"]["name"]
event_date = "20180501" #parsed_snapshot["event"]["date"]
ownership_percentage = 0.60 #shareholder["ownership_percentage"]
}
]
My challenge though is that the ["event"]["name"] an ["event"]["date"] attributes I need to fetch when looping over my snapshots i.e. the first loop (.each do |snapshot|) whereas I get my ownership_percentage when looping over shareholders - the second loop (.each do |shareholder|).
So my question is - how can I build this hash in "two" places so I can return the hash with the 3 attributes?
Appreciative of guidance/help - thank you!
You have to create a new hash for the object and append that hash to the array of objects you are creating.
def fetch_ownership_over_time(shareholder, captable)
#shareholder = Shareholder.find(shareholder.id)
#captable = Captable.find(captable.id)
#company = #captable.company.id
#ownership_over_time = []
#captable.events.collect(&:snapshot).each do |snapshot|
parsed_snapshot = JSON.parse(snapshot)
shareholder = parsed_snapshot['shareholders'].select { |s| s['id'] == #shareholder.id }.first
local_snapshot = {
'event_name' => parsed_snapshot['event']['name'],
'event_date' => parsed_snapshot['event']['date'],
'ownership_percentage' => shareholder.try(:[], "ownership_percentage") || 0
}
#ownership_over_time.push local_snapshot
end
return #ownership_over_time
end
Notice that I changed your second loop to a select. As you currently have it, you risk on pushing two percentages if the id is found twice.
EDIT:
Added functionality to use a default value if no shareholder is found.
I have a array which is inside a hash. I want know the result of the student (pass/fail) using the following array. First I have to match them with particular standard and compare their marks with the hash pass and fails. And I want to get the key pass or fail based on their mark. How to achieve this using Ruby?
array = [
{
:standard =>1
:pass=>{:tamil=>30,:eng=>25,:math=>35},
:fail=>{:tamil=>10,:eng=>15,:maths=>20}
},
{
:standard =>2,
:pass=>{:tamil=>40,:eng=>35,:math=>45},
:fail=>{:tamil=>20,:eng=>25,:maths=>30}
}
]
#student is assumed to be defined
standard = array.select {|standard| standard[:standard] == #student.standard}
eng_pass = #student.eng_mark >= standard[:pass][:eng]
eng_fail = #student.eng_mark <= standard[:fail][:eng]
return [eng_pass, eng_fail, whatever_else_you_want]
So on and forth for various topics.
The syntax in reading values from this structure is something like:
array[0][:pass][:eng]
and accordingly you can do the comparison as usual in batch:
for i in 0..#students_array.length
num = # student's score
standard = # something like array[0][:pass][:eng]
if num > standard
# something like 'put "You passed!"'
end
end
I have a table called audits which has a column 'changes' storing data in the form of hash
I would like to retrieve all entries with the following conditions:
- auditable_type = 'Expression'
- action = 'destroy'
- changes = { :EXP_SUBMISSION_FK =>'9999992642'}
I first tried the following code which returns me with nothing:
#deleted_history = Audit.find(:all, :conditions => ["auditable_type =? AND action = ? AND changes = ?",'Expression', 'destroy' , { :EXP_SUBMISSION_FK =>'9999992642'} ])
I then tried the following code which retrieves all entries in the 'audits' table with auditable_type = 'Expression' and action = 'destroy'.
I then loop through the resultset and discards all entries where EXP_SUBMISSION_FK is not equal to 9999992642. The code below returns me 5 entries/records
#deleted_history = Audit.find(:all, :conditions => ["auditable_type =? AND action = ?",'Expression', 'destroy' ])
#deleted_history.each do |test|
if test.changes['EXP_SUBMISSION_FK'] != 9999992642
#deleted_history = #deleted_history.reject { test }
end
end
I would like to know where did I go wrong with the first code example and whether there is a way of retrieving all entries with the aforementioned conditions in a much simpler way.
Thanks a lot for your help.
i'd do:
#deleted_history.select!{|hist| hist.changes['EXP_SUBMISSION_FK'] == '9999992642'}
One potential cause of failure is that you're looking for 9999992642 but you state before the value is '9999992642'
You just use something like below. I am storing element_values as a hash and i am selecting records based on the key/value pair.
scope :find_by_field_values, lambda {
|field_name, field_value|
(where("element_values like ?", "%\"#{field_name}\":\"%#{field_value}%"))
}
just try this based on your scenario.
I am using ruby-aaws to return Amazon Products and I want to enter them into my DB. I have created a model Amazonproduct and I have created a method get_amazon_data to return an array with all the product information. When i define the specific element in the array ( e.g. to_a[0] ) and then use ruby-aaws item_attributes method, it returns the name I am searching for and saves it to my DB. I am trying to iterate through the array and still have the item_attributes method work. When i don't define the element, i get this error: undefined method `item_attributes' for #Array:0x7f012cae2d68
Here is the code in my controller.
def create
#arr = Amazonproduct.get_amazon_data( :r ).to_a
#arr.each { |name|
#amazonproduct = Amazonproduct.new(params[:amazonproducts])
#amazonproduct.name = #arr.item_attributes.title.to_s
}
EDIT: Code in my model to see if that helps:
class Amazonproduct < ActiveRecord::Base
def self.get_amazon_data(r)
resp = Amazon::AWS.item_search('GourmetFood', { 'Keywords' => 'Coffee Maker' })
items = resp.item_search_response.items.item
end
end
Thanks for any help/advice.
I'm not familiar with the Amazon API, but I do observe that #arr is an array. Arrays do not usually have methods like item_attributes, so you probably lost track of which object was which somewhere in the coding process. It happens ;)
Try moving that .item_attributes call onto the object that supports that method. Maybe amazonproduct.get_amazon_data(:r), before its being turned into an array with to_a, has that method?
It's not quite clear to me what your classes are doing but to use #each, you can do something like
hash = {}
[['name', 'Macbook'], ['price', 1000]].each do |sub_array|
hash[sub_array[0]] = sub_array[1]
end
which gives you a hash like
{ 'name' => 'Macbook', 'price' => 1000 }
This hash may be easier to work with
#product = Product.new
#product.name = hash[:name]
....
EDIT
Try
def create
#arr = Amazonproduct.get_amazon_data( :r ).to_a
#arr.each do |aws_object|
#amazonproduct = Amazonproduct.new(params[:amazonproducts])
#amazonproduct.name = aws_object.item_attributes.title.to_s
end
end
Lets say I have an Array of content_categories (content_categories = user.content_categories)
I now want to add every element belonging to a certain categorie to content_categories with the category as a key and the the content-item IDs as elements of a set
In PHP something like this is possible:
foreach ($content_categories as $key => $category) {
$contentsByCategoryIDArray = Category.getContents($category[id])
$content_categories[$key][$contentsByCategoryIDArray]
}
Is there an easy way in rails to do this?
Greets,
Nico
Your question isn't really a Rails question, it's a general Ruby programming question.
Your description isn't very clear, but from what I understand, you want to group IDs for common categories using a Hash. There are various other ways of doing this, but this is easy to understand::
ary = [
'cat1', {:id => 1},
'cat2', {:id => 2},
'cat1', {:id => 3}
]
hsh = {}
ary.each_slice(2) { |a|
key,category = a
hsh[key] ? hsh[key] << category[:id] : hsh[key] = [category[:id]]
}
hsh # => {"cat1"=>[1, 3], "cat2"=>[2]}
I'm using a simple Array with a category, followed by a simple hash representing some object instance, because it makes it easy to visualize. If you have a more complex object, replace the hash entries with those objects, and tweak how you access the ID in the ternary (?:) line.
Using Enumerable.inject():
hsh = ary.each_slice(2).inject({}) { |h,a|
key,category = a
h[key] ? h[key] << category[:id] : h[key] = [category[:id]]
h
}
hsh # => {"cat1"=>[1, 3], "cat2"=>[2]}
Enumerable.group_by() could probably shrink it even more, but my brain is fading.
I'd use Enumerable#inject
content_categories = content_categories_array.inject({}){ |memo, category| memo[category] = Category.get_contents(category); memo }
Hash[content_categories.map{|cat|
[cat, Category.get_contents(cat)]
}]
Not really the right answer, because you want IDs in your array, but I post it anyway, because it's nice and short, and you might actually get away with it:
content_categories.group_by(&:category)
content_categories.each do |k,v|
content_categories[k] = Category.getContents(v)
end
I suppose it's works
If i understand correctly, content_categories is an array of categories, which needs to be turned into a hash of categories, and their elements.
content_categories_array = content_categories
content_categories_hash = {}
content_categories_array.each do |category|
content_categories_hash[category] = Category.get_contents(category)
end
content_categories = content_categories_hash
That is the long version, which you can also write like
content_categories = {}.tap do |hash|
content_categories.each { |category| hash[category] = Category.get_contents(category) }
end
For this solution, content_categories must be a hash, not an array as you describe. Otherwise not sure where you're getting the key.
contents_by_categories = Hash[*content_categories.map{|k, v| [k, Category.getContents(v.id)]}]