How can I get a single item from an Array? - ruby-on-rails

I'm using MongoDB and Mongo Mapper and need to find an embedded document inside of an array. There has to be a simpler way to do this than the way I got working which is:
#obj.subitems.each do |c|
if (c.slug.eql? params[:id])
#subitem = c # this is the variable i need
end
end
Thanks

#subitem = #obj.subitems.detect { |c| c.slug.eql? params[:id] }
http://ruby-doc.org/core-1.9.3/Enumerable.html#method-i-detect

Related

Rails - submitting JSONs to database from controller

I am working on a Rails app, and I am attempting to insert attributes from JSONs as database entries. I'm running into a problem, though, and would appreciate some guidance.
I've been able to jam a few things together and come up with something that sort of works...
def create
#report_group = Array.new
#report_group.push({location:"home", comments:"Hello, database!"}, {location:"away", comments:"Goodbye, database!"})
#report_group.each do |x|
#new_report = Report.new(x)
#new_report.user_id = current_user.id
#new_report.save
end
end
private
def report_params(params)
params.permit(:user_id,:location,:comments)
end
This is a good first step - this commits two entries to my database, one for each of the hashes pushed into #report_group, but it is suffering from a problem - the create action does not reference the report_params whitelist.
I have built several Rails apps where entries are submitted one at a time via the standard Rails form helpers, but I have never done it with multiple JSONs like this before. Trying out the syntax I'd use in a typical form helper situation
#new_report = Report.new(report_params(x))
throws the expectable error undefined method permit' for #<Hash:0x007f966b35e270> but I am not sure what else to do here.
EDIT TO SHOW SOLUTION
Big thanks to #oreoluwa for pointing me in the right direction. Here's the solution that I came up with.
def create
#report_group = Array.new
#report_group.push({location:"home", comments:"Hello, database!"}, {location:"away", comments:"Goodbye, database!"})
#report_group.each do |x|
hash = ActionController::Parameters.new(x)
#new_report = Report.new(report_params(hash))
#new_report.user_id = current_user.id
#new_report.save
end
end
private
def report_params(params)
params.permit(:user_id,:location,:comments)
end
You're getting the error because a Hash is not the same as an ActionController::Parameters. In order to use the permit method with your Hash you may need to first convert it to ActionController::Parameters, as such:
hash = {location:"home", comments:"Hello, database!"}
parameter = ActionController::Parameters.new(hash)
parameter.permit(:user_id,:location,:comments)
I don't know if that is what you're looking for, but I thought to point you in the right direction.

append data to an array rails 4

I need to append data to a variable
#celebrity = Celebrity.includes(:category).where('category_id = ?', params[:id])
test =[]
#celebrity.each do |celeb|
#vote = Vote.where('celebrity_id = ?', celeb).count
test << {vote_count:#vote}
end
when i debug 'test',
abort test.inspect
I am getting the result of
[{:vote_count=>2}, {:vote_count=>1}, {:vote_count=>0}]
but, my question is how can I append vote_count to #celebrity , can anyone please help me out
You should not do it this way, its terrible in terms of performance.
If you setup a counter_cache properly (see ref), you'd have data right away in your model instances as expected
#celebrity.each do |celeb|
celeb["vote_count"] = celeb.votes.count
end
+apneadiving is right. use counter_caches

Rails personal class Each routine

I'm kind of a newbie in some areas of ruby and rails. So I I'm writing a class to read excel depending on the extension and return the row in a each routine. Something like this:
class ExcelRead
(dependencies)
def initialize(path, sheet_n = 0)
type = File.extname(path)
if type == JitExcelRead::XLS
Spreadsheet.client_encoding = 'UTF-8'
book = Spreadsheet.open path
book_sheet = book.worksheet sheet_n
elsif type == JitExcelRead::XLSX
book = Creek::Book.new path
book_sheet = book.sheets[sheet_n]
end
#book = book
#book_sheet = book_sheet
#book_rows = book_sheet.rows
#path = path
#type = type
end
end
So this means that I call on my application
xls = ExcelRead.new(uploaded_file.filename_path)
and everything runs smooth. I have the objects I need at my disposal. My problem now is how to iterate through them. I thought that adding a method to may class like this
def each
binding.pry
end
and calling it normally on my app like so
xls.book_rows.each do |row|
end
would make me enter that code, but not really...
help?
If you added a each method to your ExcelRead class, and you create an instance of this class called xls, then you have to access it using xls.each, not xls.book_rows.each.
Using the former, you are calling the each method from the Enumerator, as book_rows is a collection.
I can only guess that you want a custom way to iterate your book_row, so i think something like this should be what you are trying to achieve:
def iterate
self.book_rows.each do |br|
# do stuff
end
end
And you call it like:
xls.iterate
But this is only a wild guess.

How do I create instance variables from an array?

I'm using Rails 3.2. Here's my code:
transports = %w(car bike)
transports.each do |transport|
#transport = transport.classify.all
end
That code is not working, but I want the results to be:
#cars = Car.all
#bikes = Bike.all
How do I do that?
transports.each do |transport|
instance_variable_set("##{transport}",
transport.classify.constantize.all)
end
Update Given that the entries in the transports array are now singular the correct code to get the result you want is
transports.each do |transport|
instance_variable_set("##{transport.pluralize}",
transport.classify.constantize.all)
end

How to store the result of my algorithm?

I have an algorithm that searches through all of my sites users, finding those which share a common property with the user using the algorithm (by going to a certain page). It can find multiple users, each can have multiple shared properties. The algorithm works fine, in terms of finding the matches, but I'm having trouble working out how to store the data so that later I'll be able to use each unit of information. I need to be able to access both the found users, and each of the respective shared properties, so I can't just build a string. This is an example of the output, being run from the perspective of user 1:
user 4
sharedproperty3
sharedproperty6
user 6
sharedproperty6
sharedproperty10
shareproperty11
What do I need to do to be able to store this data, and have access to any bit of it for further manipulation? I was thinking of a hash of a hash, but I can't really wrap my head around it. I'm pretty new to programming, and Ruby in particular. Thanks for reading!
EDIT - Here's the code. I'm fully expecting this to be the most incorrect way to do this, but it's my first try so be gentle :)
So if I'm understanding you guys correctly, instead of adding the interests to a string, I should be creating an array or a hash, adding each interest as I find it, then storing each of these in an array or hash? Thanks so much for the help.
def getMatchedUsers
matched_user_html = nil
combined_properties = nil
online_user_list = User.logged_in.all
shared_interest = false
online_user_list.each do |n| # for every online user
combined_properties = nil
if n.email != current_user.email # that is not the current user
current_user.properties.each do |o| # go through all of the current users properties
n.properties.each do |p| # go through the online users properties
if p.interestname.eql?(o.interestname) # if the online users property matches the current user
shared_interest = true
if combined_properties == nil
combined_properties = o.interestname
else
combined_properties = combined_properties + ", " + o.interestname
end
end
end
if shared_interest == true
matched_user_html = n.actualname + ": " + combined_properties
end
end
end
end
return matched_user_html
render :nothing => true
end
This returns an array of hashes with all users and their corresponding sharedproperties.
class User
def find_matching_users
returning Array.new do |matching_users|
self.logged_in.each do |other_user|
next if current_user == other_user # jump if current_user
# see http://ruby-doc.org/core/classes/Array.html#M002212 for more details on the & opreator
unless (common_properties = current_user.properties & other_user.properties).empty?
matching_users << { :user => other_user, :common_properties => common_properties }
end
end
end
end
end
In your view you can do something like this:
<%- current_user.find_matching_users.each do |matching_user| -%>
<%-# you can acccess the user with matching_user[:user] -%>
<%-# you can acccess the common properties with matching_user[:common_properties] -%>
<%- end -%>
You can use a hash table with the key being the user object and the value being an array of the shared properties . This is assuming that you first need to do a lookup based on the user .
Something like this :
#user_results = { user1 => [sharedproperty3,sharedproperty7] , user2 => [sharedproperty10,sharedproperty11,sharedproperty12]}
You can then acces the values like :
#user_results[user1]
or you can also iterate over all the keys using #user_results.keys

Resources