I have a collection/array in rails, transformed to json it looks like this:
#collection = [{"order_number":"123","item":"Paper"},{"order_number":"567","item":"Ruler"},{"order_number":"344","item":"Pen"},{"order_number":"342","item":"Pencil"},{"order_number":"877","item":"Keyboard"}]
I would like to pick the item with the order_number "342" and put it at the last position of the collection, so the new collection looks like this:
#collection = [{"order_number":"123","item":"Paper"},{"order_number":"567","item":"Ruler"},{"order_number":"344","item":"Pen"},{"order_number":"877","item":"Keyboard"},{"order_number":"342","item":"Pencil"}]
In theory, it would look like this:
#collection.last = #collection[3]
but that is obviously not fancy ruby style nor would it re-sort the array as in my example.
Also I don't know the index of the item as it can change depending on what the user shops.
how about:
#collection << #collection.delete_at[#collection.index{|x| x[:order_number] == "342"}]
This basically searches the index of element with :order_number 342 first, uses that index to delete it, and then store the deleted element at the end again.
You can also use the partition method:
#collection = #collection.partition { |h| h['order_number'] != '342' }.flatten
Just split your collection on two (without 342 order and with 342 order), then just join them. It should looks like:
#collection = #collection.select {|e| e[:order_number] != '342' } + #collection.select {|e| e[:order_number] == '342' }
If you have an index of an item it boils down to
#collection << #collection.delete_at(3)
If you don't, you could try finding it using
#collection.find_index{ |el| el["order_number"] == "123" }
Alternative you can try this too:
> #collection.each_with_index{ |key,value| #collection.push(#collection.delete_at(value)) if key[:order_number] == "344" }
#=>[{:order_number=>"123", :item=>"Paper"}, {:order_number=>"567", :item=>"Ruler"}, {:order_number=>"342", :item=>"Pencil"}, {:order_number=>"877", :item=>"Keyboard"}, {:order_number=>"344", :item=>"Pen"}]
Related
I have a call to ActiveRecord in my controller as so:
#configurations = EmailConfiguration.where(customer_id: '1', email_template: '1')
This will return all EmailConfigurations that have the correct parameters. Each record has a field_id and a the_value. I want to display the value in the view:
#configurations.where(field_id: 1).the_value
What do I need to add to the view to select a certain record within the collection that is returned by the database?
You can use select for a quick filter on arrays
#configurations.select {|c| c.field_id == 1}
that will return all collections with field_id = 1. If you know there is only one, you could chain it for a direct output:
#configurations.select {|c| c.field_id == 1}.first.the_value
#configurations.where(field_id: 1)
returns a collection of objects(array) even if there is only one result. If you would like to show only one you can do as suggested above:
#configurations.select {|c| c.field_id == 1}.first.the_value
If you want to show all of the "the_values" you can do
field_1_configs = #configurations.select do |c| c.field_id == 1
end
field_1_configs.map{|config| config.the_value }
I have this function:
medIntCategory = MedicalInterventionCategory.find_by_category_text(category.category.text)
However now I have a list of categories called categories.
I would like to execute the above code for each category and get back a list of medIntCategories, but with no duplicates.
Is there a simple way to do this since I am only dealing with integers?
in simple terms:
categoryList = []
for each category in categories do
categoryList += MedicalInterventionCategory.find_by_category_text(category.category.text)
end
But with duplicate checking
This sounds like a job for Array#map and Array#uniq:
category_list = categories.map{|category|
MedicalInterventionCategory.find_by_category_text(category.category.text)
}.uniq
#result=Array.new
##assuming that it returns an array
medIntCategory = MedicalInterventionCategory.find_by_category_text(category.category.text)
##get the first category obtained
#result << medIntCategory
if medIntCategory.present?
medIntCategory.each do |m|
##add in same array only if not present
if !#result.include?(m)
#result << m.find_by_category_text(c.category.text)
end
end
##return a unique value array
#result.flatten.compact.uniq unless #result.blank?
end
HOPE IT HELPS
I think this would work
category_list = []
categories.each do |category|
category_list << MedicalInterventionCategory.find_by_category_text(category.category.text).distinct
end
Is it possible to parse an array of objects to select them by attribute? I have a situation where I need to display all objects of a model grouped by an attribute on the index page. What I had been doing in my controller is this...
#xx_controller.rb
#group1 = City.where(:population => 'big')
#group2 = City.where(:population => 'medium')
#group3 = City.where(:population => 'small')
But I'd prefer to do something like this in the controller...
#cities = City.all
And in my view something along the lines of a query, rather than prepackaged instance variables -
#cities.where....
Any thoughts?
If you don't mind loading everything at once from the database, you can do:
#cities = City.all.group_by(&:population)
Which returns a hash whose keys are the possible values for the population attribute.
Then, on your view, you can access the cities on each 'group' by doing #cities['small'], #cities['medium'] and so on.
Do you mean something like this?
#cities = City.all
small_cities = #cities.select { |city| city.population == 'small' }
medium_cities = #cities.select { |city| city.population == 'medium' }
big_cities = #cities.select { | city| city.population == 'big' }
Say I have an array, and I use the keep_if or select methods to delete everything but one object for the array -- is there a way to take that object out of the array, so it's not an array any more?
For example, the way my models are set up, previous and current will only ever have one object.
def more_or_less?(project, current_day)
words = project.words
current = words.select {|w| w.wrote_on == current_day}
previous = words.select {|w| w.wrote_on == (current_day - 1.day)}
end
So, if I want to do a comparison, like if current.quantity > previous.quantity -- I've resorted to actually writing if current.last.quantity > previous.last.quantity but I'm assuming there's a more idiomatic way?
If you're deleting all but one entries, why not use find to choose the one thing you care about? Something like this:
def more_or_less?(project, current_day)
words = project.words
current = words.find { |w| w.wrote_on == current_day }
previous = words.find { |w| w.wrote_on == (current_day - 1.day) }
if current.quantity > previous.quantity
#...
end
end
If you're in ActiveRecord land, then you can use detect as derp says or to_a to get a plain array that you can use find on:
def more_or_less?(project, current_day)
words = project.words
current = words.detect { |w| w.wrote_on == current_day }
previous = words.to_a.find { |w| w.wrote_on == (current_day - 1.day) }
if current.quantity > previous.quantity
#...
end
end
detect is an alias for find, maybe that would work
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