There's a similar answer but it won't apply to me, but maybe will help someone: here
So, I have a loop and need to input a value into each of 20 variables, called product1, product2, ... , product20.
Im using nokogiri to change the values from a page, and manually it works:
li.content = #site.product1
li = #doc.css('li')[1]
But to avoid code repetition and also I have more cases like that one in my app im trying to make a loop, but it won't work since now.
What it need to do:
(1..20).each do |i|
li = #doc.css('li')[i]
li.content = #site.producti
end
Thanks
TRy
(0...20).each do |i|
li = #doc.css('li')[i]
li.content = #site.send("product#{i}")
end
Related
class ScraperController < ApplicationController
def show
mechanize = Mechanize.new
website = mechanize.get('https://website.com/')
$max = 2
$counter = 0
$link_to_click = 2
#names = []
while $counter <= $max do
#names.push(website.css('.memName').text.strip)
website.link_with(:text => '2').text.strip.click
$link_to_click += 1
$counter += 1
end
end
end
I am trying to scrape 20 items off of each page and then click on the link at the bottom (1, 2, 3, 4, 5, etc.). However, I get the error as seen in the title which tells me that I cannot click the string. So it recognizes that the button '2' exists but will tell me if cannot click it. Ideally, once this is sorted out, I wanted to the use the $link_to_click variable as a way to replace the '2' so that it will increment each time but it always comes back as nil. I have also changed it to .to_s with the same result.
If I remove the click all together, it will scrape the same page 3 times instead of moving onto the next page. I have also removed the text.strip part before the .click and it will do the same thing. I have tried many variations but have had no luck.
I would really appreciate any advice you could offer.
I ended up reviewing the articles I was referencing to solve this and came to this conclusion.
I changed the website_link to website = website.link_with(:text => $link_to_click.to_s).click (because it only worked as a string) and it printed out the first page, second and each one thereafter.
These are the articles that I was referencing to learn how to do this.
http://docs.seattlerb.org/mechanize/GUIDE_rdoc.html
and
https://readysteadycode.com/howto-scrape-websites-with-ruby-and-mechanize
In my Rails application, in a model, I am trying to use the loop index x in the following method, and I can't figure out how to get the value:
def set_winners ## loops over 4 quarters
1.upto(4) do |x|
qtr_[x]_winner.winner = 1
qtr_[x]_winner.save
end
end
I'm going to keep searching but any help would be greatly appreciated!
edit: So I guess I can't do that! Here is the original method I was trying to refactor in full by looping four times:
def set_winners
## set all 4 quarter's winning squares
home_qtr_1 = game.home_q1_score.to_s.split('').last.to_i
away_qtr_1 = game.away_q1_score.to_s.split('').last.to_i
qtr_1_winner = squares.where(xvalue:home_qtr_1, yvalue:away_qtr_1).first
qtr_1_winner.winner = 1
qtr_1_winner.save
home_qtr_2 = game.home_q2_score.to_s.split('').last.to_i
away_qtr_2 = game.away_q2_score.to_s.split('').last.to_i
qtr_2_winner = squares.where(xvalue:home_qtr_2, yvalue:away_qtr_2).first
qtr_2_winner.winner = 1
qtr_2_winner.save
home_qtr_3 = game.home_q3_score.to_s.split('').last.to_i
away_qtr_3 = game.away_q3_score.to_s.split('').last.to_i
qtr_3_winner = squares.where(xvalue:home_qtr_3, yvalue:away_qtr_3).first
qtr_3_winner.winner = 1
qtr_3_winner.save
home_qtr_4 = game.home_q4_score.to_s.split('').last.to_i
away_qtr_4 = game.away_q4_score.to_s.split('').last.to_i
qtr_4_winner = squares.where(xvalue:home_qtr_4, yvalue:away_qtr_4).first
qtr_4_winner.winner = 1
qtr_4_winner.save
end
Is there a better way to do this if it's bad practice to dynamically change attribute names?
It looks like you are trying to do a PHP-like trick in a language that doesn't support it, and where we recommend NOT doing it because it results in code that is very difficult to debug due to the dynamically named variables.
It looks like you want to generate a variable name using:
qtr_[x]_winner
to create something like:
qtr_1_winner
Instead, consider creating an array named qtr_winner containing your objects and access the elements like:
qtr_winner[1]
or
qtr_winner[2]
etc.
You could create a hash to do a similar thing:
qtr_winner = {}
qtr_winner[1] = 5
then later access it using qtr_winner[1] and get 5 back or
qtr_winner[1].winner = 1
The determination of whether to use a hash or an array is whether you need to walk the container, or need random access. If you are always indexing into it using a value, then it's probably a wash about which is faster.
Based on your edit, you don't need dynamic variables. The only thing that changes in your loop is game.home_qN_score, so that's what the focus of your refactoring should be. Given that, here's a viable solution:
1.upto(4) do |i|
home_qtr = game.send("home_q#{i}_score)".to_s.split('').last.to_i
away_qtr = game.send("away_q#{i}_score)".to_s.split('').last.to_i
winner = squares.where(xvalue:home_qtr, yvalue:away_qtr).first
winner.winner = 1
winner.save
end
Original answer:
If qtr_1_winner, etc. are instance methods, you can use Object#send to achieve what you want:
def set_winners ## loops over 4 quarters
1.upto(4) do |x|
send("qtr_#{x}_winner").winner = 1
send("qtr_#{x}_winner").save
end
end
I've got a problem in doing some metaprogramming in Ruby / Rails which must be minor, but I can't get the clue.
I wan't to assign values to an active record relation, with my model having attributes:
MyModelClass.p1_id,
.p2_id,
...
.p8_id
SecondModel.position #Integer in (1..8)
I now want to do the following
sms = SecondModel.where(:xyz => 'bla')
sms.each do |sm|
mmc = MyModellClass.first
mmc.#somehow construct method here = sm.id
end
So that somehow this is accomplished
mmc.p1_id = sm.id
mmc.p2_id = sm.id
..
mmc.p8_id = sm.id
To sum up: I want to create that p*n*_id stuff dynamically, but I can't find out, how to tell Ruby, that this should be a method. I tried so far:
mmc.send('p#{sm.position.to_s}_id'.to_sym) = sm.id
But this doesn't work. Any clues?
You were close. Try this:
mmc.send("p#{sm.position.to_s}_id=", sm.id)
Here we call the method with = and pass the value of attribute as the second argument of send
I'm building a conditions hash to run a query but I'm having a problem with one specific case:
conditions2 = ['extract(year from signature_date) = ?', params[:year].to_i] unless params[:year].blank?
conditions[:country_id] = COUNTRIES.select{|c| c.geography_id == params[:geographies]} unless params[:geographies].blank?
conditions[:category_id] = CATEGORY_CHILDREN[params[:categories].to_i] unless params[:categories].blank?
conditions[:country_id] = params[:countries] unless params[:countries].blank?
conditions['extract(year from signature_date)'] = params[:year].to_i unless params[:year].blank?
But the last line breaks everything, as it gets interpreted as follows:
AND ("negotiations"."extract(year from signature_date)" = 2010
Is there a way to avoid that "negotiations"." is prepended to my condition?
thank you,
P.
For something like this, you'll probably have to write your own SQL with find_by_sql. Still wrap it in a method in your model so your model's friends can access it nicely.
I have a huge XML(>400MB) containing products. Using a DOM parser is therefore excluded, so i tried to parse and process it using a pull parser. Below is a snippet from the each_product(&block) method where i iterate over the product list.
Basically, using a stack, i transform each <product> ... </product> node into a hash and process it.
while (reader.read)
case reader.node_type
#start element
when Nokogiri::XML::Node::ELEMENT_NODE
elem_name = reader.name.to_s
stack.push([elem_name, {}])
#text element
when Nokogiri::XML::Node::TEXT_NODE, Nokogiri::XML::Node::CDATA_SECTION_NODE
stack.last[1] = reader.value
#end element
when Nokogiri::XML::Node::ELEMENT_DECL
return if stack.empty?
elem = stack.pop
parent = stack.last
if parent.nil?
yield(elem[1])
elem = nil
next
end
key = elem[0]
parent_childs = parent[1]
# ...
parent_childs[key] = elem[1]
end
The issue is on self-closing tags (EG <country/>), as i can not make the difference between a 'normal' and a 'self-closing' tag. They both are of type Nokogiri::XML::Node::ELEMENT_NODE and i am not able to find any other discriminator in the documentation.
Any ideas on how to solve this issue?
There is a feature request on project page regarding this issue (with the corresponding failing test).
Until it will be fixed and pushed into the current version, we'll stick with good'ol
input_text.gsub! /<([^<>]+)\/>/, '<\1></\1>'
Hey Vlad, well I am not a Nokogiri expert but I've done a test and saw that the self_closing?() method works fine on determining the self closing tags. Give it a try.
P.S. : I know this is an old post :P / the documentation is HERE