Ruby Find and Return Objects in an Array Based on an Attribute

Ruby find and return objects in an array based on an attribute

array_of_objects.select { |favor| favor.completed == false }

Will return all the objects that's completed is false.

You can also use find_all instead of select.

Return object after performing intersection of two arrays based on attribute

you can:

1 :

override the eql?(other) method then the array intersection will work

class Link < ApplicationRecord
  def eql?(other)
    self.class == other.class && self.id == other&.id # classes comparing class is a guard here
  end
  
  # you should always update the hash if you are overriding the eql?() https://stackoverflow.com/a/54961965/5872935
  def hash
    self.id.hash
  end 
end

2:

use array.select:

array_links.flat_map {|i| selected_links.select {|k|  k.user_id == i.user_id }}

get element in array based on element's attributes

Ruby's selected method is probably what you're looking for.

obj_array.select { |obj| obj.type == type1 }

Obviously make sure you define type1.

Searching array of objects for item in Ruby

Your array contains a Hash, with keys that are symbols (in hashes, key: value is a shorthand for :key => value). Therefore, you need to replace item.login with item[:login]:

name = "joseph"

array = [{"login":"joseph","id":4,"url":"localhost/joe","description":nil},
{"login":"billy","id":10,"url":"localhost/billy","description":nil}]

arrayIndex = array.find_index{ |item| item[:login] == name }

puts arrayIndex

The code above retrieves the index at which the sought object is in the array. If you want the object and not the index, use find instead of find_index:

arrayItem = array.find{ |item| item[:login] == name }

Also, note that in Ruby, null is actually called nil.

Iterate over Array of Objects and Return Attributes

Use Array#map to invoke the title method on each and create a new array with the results:

loe.article.map(&:title)

The above is shorthand for

loe.article.map{ |o| o.title }

Return object attribute from array of objects in Ruby

You can avoid the creation of a @results variable which you need to return explicitly by using the Enumerable#map method, something like this:

items.map do |attribs|
  a = attribs.item_attributes
  {:label => "#{a.title.to_s[0,85] unless a.title.nil?}",
             :value => "#{a.title.to_s unless a.title.nil?}",
             :img => "#{attribs.medium_image.url.to_s unless attribs.medium_image.url.nil?}"
  }
end

Enumerable#map returns an array of the return values of running the supplied block on each item in the receiving array. So if the intention in your original method is to return @results, you might be better off using map.

Incidentally, even if you put 'return @results' at the end of the method as it stands, it will only give the attributes computed in the last iteration of the loop, since you reset @results to [] each time the block is called. You could either avoid this by initializing @results to [] before the loop or by avoiding it entirely using map.

Find duplicate objects in an array based on a subset of attributes in Ruby

cars.group_by{|car| [car.engine_size, car.accelaration, car.mass]}

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