A user has multiple libraries, and each library has multiple books. I want to know if a user has a book in one of his libraries. I'm calling this method with: current_user.has_book?(book):
def has_book?(book)
retval = false
libraries.each do |l|
retval = true if l.books.include?(book)
end
return retval
end
Can my method be refactored?
def has_book?(book)
libraries.any?{|lib| lib.books.include?book}
end
Pretty much the simplest i can imagine.
Not Nil safe though.
def has_book?(book)
libraries.map { |l| l.books.include?(book) }.any?
end
map turns collection of library objects into collection of bools, depending do they include the book, and any? returns true if any of the elements in the array is true.
this has fewer lines, but your original solution could be more efficient if you return true as soon as you find a library that contains the book.
def has_book?(book)
libraries.each do |l|
return true if l.books.include?(book)
end
return false
end
btw. both php and ruby appeared about the same time.
This looks to be the most minified version, I can't see any way to minify it more:
def has_book?(a)c=false;libraries.each{|b|c=true if b.books.include?a};c end
I don't know why #Зелёный removed his answer but this was a good one IMO so I paste it here:
def has_book?(book)
libraries.includes(:books)
.where(books: {id: book.id})
.any?
end
Related
I've got a service object which creates the CSV file from assigned data. The call method is pretty simple:
def initialize(data)
#data = data
end
def call
CSV.generate(headers: true, col_sep: ';') do |csv|
csv << csv_headers
data.uniq.each do |contract|
next if contract.transient
payment_details = [
next_payment_date(contract),
I18n.t("contracts.interval_options.#{contract.recurring_transaction_interval&.name}"),
]
csv << payment_details
end
end
end
private
def next_payment_date(contract)
if contract.upcoming_installment.nil?
I18n.t('tables.headers.no_next_payment_date')
else
contract.upcoming_installment.transaction_date.to_s
end
end
It works well but I don't think next_payment_date is really fancy if block, I'm wondering is it possible to replace it with some guard instead?
Because of rubocop I cannot use:
contract.upcoming_installment.nil? ? I18n.t('tables.headers.no_next_payment_date') : contract.upcoming_installment.transaction_date.to_s
In my opinion, the method looks fine as it is. Having better readability is a profitable trade-off for increasing LOCs or introducing methods. That said, there are ways where you can make it an one liner if you really fancy.
contract.upcoming_installment&.transaction_date || I18n.t('tables.headers.no_next_payment_date')
Ruby's safe navigation &. will return nil if upcoming_installment is nil which should fallback to the I18n.
In my app that I am building to learn Rails and Ruby, I have below iteration/loop which is not functioning as it should.
What am I trying to achieve?
I am trying to find the business partner (within only the active once (uses a scope)) where the value of the field business_partner.bank_account is contained in the field self_extracted_data and then set the business partner found as self.sender (self here is a Document).
So once a match is found, I want to end the loop. A case exists where no match is found and sender = nil so a user needs to set it manually.
What happens now, is that on which ever record of the object I save (it is called as a callback before_save), it uses the last identified business partner as sender and the method does not execute again.
Current code:
def set_sender
BusinessPartner.active.where.not(id: self.receiver_id).each do |business_partner|
bp_bank_account = business_partner.bank_account.gsub(/\s+/, '')
rgx = /(?<!\w)(#{Regexp.escape(bp_bank_account)})?(?!\w)/
if self.extracted_data.gsub(/\s+/, '') =~ rgx
self.sender = business_partner
else
self.sender = nil
end
end
end
Thanks for helping me understand how to do this kind of case.
p.s. have the pickaxe book here yet this is so much that some help / guidance would be great. The regex works.
Using feedback from #moveson, this code works:
def match_with_extracted_data?(rgx_to_match)
extracted_data.gsub(/\s+/, '') =~ rgx_to_match
end
def set_sender
self.sender_id = matching_business_partner.try(:id) #unless self.sender.id.present? # Returns nil if no matching_business_partner exists
end
def matching_business_partner
BusinessPartner.active.excluding_receiver(receiver_id).find { |business_partner| sender_matches?(business_partner) }
end
def sender_matches?(business_partner)
rgx_registrations = /(#{Regexp.escape(business_partner.bank_account.gsub(/\s+/, ''))})|(#{Regexp.escape(business_partner.registration.gsub(/\s+/, ''))})|(#{Regexp.escape(business_partner.vat_id.gsub(/\s+/, ''))})/
match_with_extracted_data?(rgx_registrations)
end
In Ruby you generally want to avoid loops and #each and long, procedural methods in favor of Enumerable iterators like #map, #find, and #select, and short, descriptive methods that each do a single job. Without knowing more about your project I can't be sure exactly what will work, but I think you want something like this:
# /models/document.rb
class Document < ActiveRecord::Base
def set_sender
self.sender = matching_business_partner.try(:id) || BusinessPartner.active.default.id
end
def matching_business_partners
other_business_partners.select { |business_partner| account_matches?(business_partner) }
end
def matching_business_partner
matching_business_partners.first
end
def other_business_partners
BusinessPartner.excluding_receiver_id(receiver_id)
end
def account_matches?(business_partner)
rgx = /(?<!\w)(#{Regexp.escape(business_partner.stripped_bank_account)})?(?!\w)/
data_matches_bank_account?(rgx)
end
def data_matches_bank_account?(rgx)
extracted_data.gsub(/\s+/, '') =~ rgx
end
end
# /models/business_partner.rb
class BusinessPartner < ActiveRecord::Base
scope :excluding_receiver_id, -> (receiver_id) { where.not(id: receiver_id) }
def stripped_bank_account
bank_account.gsub(/\s+/, '')
end
end
Note that I am assigning an integer id, rather than an ActiveRecord object, to self.sender. I think that's what you want.
I didn't try to mess with the database relations here, but it does seem like Document could include a belongs_to :business_partner, which would give you the benefit of Rails methods to help you find one from the other.
EDIT: Added Document#matching_business_partners method and changed Document#set_sender method to return nil if no matching_business_partner exists.
EDIT: Added BusinessPartner.active.default.id as the return value if no matching_business_partner exists.
I'm writing a helper method to determine if current has any pending reviews to write. If there is a pending review, simply print a line in the view.
My helper is putting exactly the right stuff to the console, however I'm struggling with how to simply return it. In this scenario, current user has an id: 4.
My Code:
def review_pending
gallery = current_user.galleries.first
if gallery
if gallery.permissions.accepted
gallery.permissions.accepted.each do |p|
return true if p.user.reviews.find_by_reviewer_id(!current_user)
puts "already written review: #{p.user.reviews.find_by_reviewer_id(4)} - prints correctly"
end
end
end
end
My goal: if there is a user from the list that current user has not yet reviewed return true.
Thanks!!!
Thanks for all your pointers!
I had forgotten/learned 2 things to make it work:
First, if nil is returned, ruby returns the last returned value which in my case was true (if gallery.permissions.accepted).
Secondly, I placed the "!" before current_user, and should have placed it before the entire line.
Corrected Code:
def review_pending
gallery = current_user.galleries.first
if gallery
gallery.permissions.accepted.each do |p|
return !p.user.reviews.find_by_reviewer_id(current_user.id)
end
end
return false
end
My search method is smelly and bloated, and I need some help refactoring it. I'm new to Ruby, and I haven't figured out how to leverage it effectively, which leads to bloated methods like this:
# discussion.rb
def self.search(params)
# If there is a search query, use Tire gem for fulltext search
if params[:query].present?
tire.search(load: true) do
query { string params[:query] }
end
# Otherwise grab all discussions based on category and/or filter
else
# Grab all discussions and include the author
discussions = self.includes(:author)
# Filter by category if there is one specified
discussions = discussions.where(category: params[:category]) if params[:category]
# If params[:filter] is provided, user it
if params[:filter]
case params[:filter]
when 'hot'
discussions = discussions.open.order_by_hot
when 'new'
discussions = discussions.open.order_by_new
when 'top'
discussions = discussions.open.order_by_top
else
# If params[:filter] does not match the above three states, it's probably a status
discussions = discussions.order_by_new.where(status: params[:filter])
end
else
# If no filter is passed, just grab discussions by hot
discussions = discussions.open.order_by_hot
end
end
end
STATUSES = {
question: %w[answered],
suggestion: %w[started completed declined],
problem: %w[solved]
}
scope :order_by_hot, order('...') DESC, created_at DESC")
scope :order_by_new, order('created_at DESC')
scope :order_by_top, order('votes_count DESC, created_at DESC')
This is a Discussion model that can be filtered (or not) by a category: question, problem, suggestion.
All discussions or a single category can be filtered further by hot, new, votes, or status. Status is a hash in the model and it has several values depending on the category (status filter only appears if params[:category] is present).
Complicating matters is a fulltext search feature using Tire
But my controller looks nice and tidy:
def index
#discussions = Discussion.search(params)
end
Can I dry this up/refactor it a little, maybe using meta programming or blocks? I managed to extract this out of the controller, but then ran out of ideas. I don't know Ruby well enough to take this further.
For starters, "Grab all discussions based on category and/or filter" can be a separate method.
params[:filter] is repeated many times, so take that out at the top:
filter = params[:filter]
You can use
if [:hot, :new, :top].incude? filter
discussions = discussions.open.send "order_by_#{filter}"
...
Also, factor out if then else if case else statements. I prefer break into separate methods and return early:
def do_something
return 'foo' if ...
return 'bar' if ...
'baz'
end
discussions = discussions... appears many times, but looks weird. Can you use return discussions... instead?
Why does the constant STATUSES appear at the end? Usually constants appear at the top of the model.
Be sure to write all your tests before refactoring.
To respond to the comment about return 'foo' if ...:
Consider:
def evaluate_something
if a==1
return 'foo'
elsif b==2
return 'bar'
else
return 'baz'
end
end
I suggest refactoring this to:
def evaluate_something
return 'foo' if a==1
return 'bar' if b==2
'baz'
end
Perhaps you can refactor some of your if..then..else..if statements.
Recommended book: Clean Code
I have done this in Rails 2.3.10 and 3.0.3 and it works
def self.find(*args)
records = super
# Manipulate Records here.
end
I am looking for a base finder function in Rails 3 which I can replace for this functionality to be applied to Post.all, Post.first, Post.last etc.
My advice ... make a scope or a class method to do this instead:
e.g.
scope :my_scope, lambda {|...| ...}
then to apply
TheClass.my_scope.all
TheClass.my_scope.first
TheClass.my_scope.last
all, first, and last are all just wrappers for find so redefining find should affect all of those. Take a look at how they're implemented in ActiveRecord::FinderMethods.
I believe you are looking for this:
# File activerecord/lib/active_record/relation/finder_methods.rb, line 95
def find(*args)
return to_a.find { |*block_args| yield(*block_args) } if block_given?
options = args.extract_options!
if options.present?
apply_finder_options(options).find(*args)
else
case args.first
when :first, :last, :all
send(args.first)
else
find_with_ids(*args)
end
end
end
This will do what the original question was asking.
def self.find_by_sql(*args)
records = super
# Manipulate Records here
return records
end