I am new to ruby 1.9.2. How to generate CSV file in a single ruby script file?
Here, I wrote a ruby script,
require 'rubygems'
require 'pg'
require 'active_record'
require 'csv'
class AttachEmail
def generate_csv
begin
filename = "csvout.csv"
users = User.all
users.each do |u|
products = Product.find(:all,:conditions=>["user_id=?",u.id])
CSV.open(filename, 'w') do |csv|
# header row
user_name = u.name
csv << ['Report']
csv << ['Name','Product', 'Item Count']
products.each do |product|
csv << [user_name, product.title,product.count]
end
end
end
rescue Exception => e
puts e
end
end
generate= AttachEmail.new
generate.generate_csv
When i run this script.it will produce output like below,
A B C
0 Report
1 Name,Product,Item Count
2 user1,PD123,10,990
But I need output like, separate column, Please can you kind me ? Thanks in advance
First of all, you need to swap loops if you are trying to put all the user data in the same file, and not overwrite it for every user:
CSV.open(filename, 'w') do |csv|
users.each do |u|
products = Product.find(:all,:conditions=>["user_id=?",u.id])
Next, fix your Excel (I suspect the output is taken from it, right?) to use comma as a separator, not a "space or comma".
Come back with the file contents attached and an example of CSV file which works for you if it still doesn't work.
Related
I have this code here which outputs a CSV, but when I open the CSV file its just has a 0 in the first two columns.
require 'rubygems'
require 'nokogiri'
require 'open-uri'
require 'csv'
page = Nokogiri::HTML(open("https://www.drugs.com/pharmaceutical-
companies.html"))
puts page.class #=> Nokogiri::HTML::Document
pharma_links = page.css("div.col-list-az a")
link= pharma_links.each{|link| puts link['href'] }
company = pharma_links.each{|link| puts link.text}
CSV.open("/Users/file.csv", "wb") do |csv|
csv << [company, link]
end
The problem is that pharma_links.each{|link| ...} returns the ENTIRE enumerator, so if you do this once for company and once for link you now have two new arrays. You then have to re-map each company & link in a new array / hash (or by index if you are lazy AND you know for certain nothing went wrong in the either .each call)
To avoid this, simply construct the CSV while you are looping through the data. For each line of the CSV you expect one pharma_links 'line', so iterate through each at the same time:
require 'nokogiri'
require 'open-uri'
require 'csv'
page = Nokogiri::HTML(open("https://www.drugs.com/pharmaceutical-companies.html"))
# puts page.class #=> Nokogiri::HTML::Document
pharma_links = page.css("div.col-list-az a")
# Create the CSV and iterate through the links while creating it
# You can also add headers to the CSV on instantiation
CSV.open("file.csv", "wb", write_headers: true, headers: ['url','description']) do |csv|
pharma_links.each do |link|
puts "Adding #{link.text}" # prove that it works :)
csv << [link['href'], link.text]
end
end
This is killing me and searching here and the big G is confusing me even more.
I followed the tutorial at Railscasts #190 on Nokogiri and was able to write myself a nice little parser:
require 'rubygems'
require 'nokogiri'
require 'open-uri'
url = "http://www.target.com/c/movies-entertainment/-/N-5xsx0/Ntk-All/Ntt-wwe/Ntx-matchallpartial+rel+E#navigation=true&facetedValue=/-/N-5xsx0&viewType=medium&sortBy=PriceLow&minPrice=0&maxPrice=10&isleaf=false&navigationPath=5xsx0&parentCategoryId=9975218&RatingFacet=0&customPrice=true"
doc = Nokogiri::HTML(open(url))
puts doc.at_css("title").text
doc.css(".standard").each do |item|
title = item.at_css("span.productTitle a")[:title]
format = item.at_css("span.description").text
price = item.at_css(".price-label").text[/\$[0-9\.]+/]
link = item.at_css("span.productTitle a")[:href]
puts "#{title}, #{format}, #{price}, #{link}"
end
I'm happy with the results and able to see it in the Windows console. However, I want to export the results to a CSV file and have tried numerous ways (with no luck) and I know I'm missing something. My latest updated code (after downloading the html files) is below:
require 'rubygems'
require 'nokogiri'
require 'csv'
#title = Array.new
#format = Array.new
#price = Array.new
#link = Array.new
doc = Nokogiri::HTML(open("index1.html"))
doc.css(".standard").each do |item|
#title << item.at_css("span.productTitle a")[:title]
#format << item.at_css("span.description").text
#price << item.at_css(".price-label").text[/\$[0-9\.]+/]
#link << item.at_css("span.productTitle a")[:href]
end
CSV.open("file.csv", "wb") do |csv|
csv << ["title", "format", "price", "link"]
csv << [#title, #format, #price, #link]
end
It works and spits a file out for me, but just the last result. I followed the tutorial at Andrew!: WEb Scraping... and trying to mix what I'm trying to achieve with someone else's process is confusing.
I assume it's looping through all of the results and only printing the last. Can someone give me pointers on how I should loop this (if that's the problem) so that all the results are in their respective columns?
Thanks in advance.
You're storing values in four arrays, but you're not enumerating the arrays when you generate your output.
Here is a possible fix:
CSV.open("file.csv", "wb") do |csv|
csv << ["title", "format", "price", "link"]
until #title.empty?
csv << [#title.shift, #format.shift, #price.shift, #link.shift]
end
end
Note that this is a destructive operation that shifts the values off of the arrays one at a time, so in the end they will all be empty.
There are more efficient ways to read and convert the data, but this will hopefully do what you want for now.
There are several things you could do to write this more in the "Ruby way":
require 'rubygems'
require 'nokogiri'
require 'csv'
doc = Nokogiri::HTML(open("index1.html"))
CSV.open('file.csv', 'wb') do |csv|
csv << %w[title format price link]
doc.css('.standard').each do |item|
csv << [
item.at_css('span.productTitle a')[:title]
item.at_css('span.description').text
item.at_css('.price-label').text[/\$[0-9\.]+/]
item.at_css('span.productTitle a')[:href]
]
end
end
Without sample HTML it's not possible to test this, but, based on your code, it looks like it'd work.
Notice that in your code you're using instance variables. They're not necessary because you aren't defining a class to have an instance of. You can use local values instead.
I have a csv file that has 7000+ records that I process/manipulate and export to a new csv file. I have no issues doing that and everything works as expected.
I would like to change the process to where it breaks the output into multiple files. So instead of writing all 7000+ rows to the new csv file it would write the first 1000 rows to newexport1.csv and the next 1000 rows to newexport2.csv until it reaches the end of the data.
Is there an easy way to do this with CSV in Ruby 1.9?
My current write method:
CSV.open("#{PATH_TO_EXPORT_FILE}/newexport.csv", "w+", :col_sep => '|', :headers => true) do |f|
export_rows.each do |row|
f << row
The short answer is "no". You'll want to adjust your current code to split up the set and then dump each subset to a different file. This ought to be pretty close:
export_rows.each_slice(1000).with_index do |rows, idx|
CSV.open("#{PATH_TO_EXPORT_FILE}/newexport-#{idx.to_s}.csv", "w+", :col_sep => '|', :headers => true) do |f|
rows.each { |row| f << row }
end
end
Yes, there is.
It's embedded in Ruby 1.9
Check this link
To read:
CSV.foreach("path/to/file.csv") do |row|
# manipulate the content
end
To write:
CSV.open("path/to/file.csv", "wb") do |csv|
csv << ["row", "of", "CSV", "data"]
csv << ["another", "row"]
# something else
end
I think that you'll need to combine one inside the other.
FasterCSV is the standard CSV library since ruby 1.9, you can find a lot of example code in the examples folder:
https://github.com/JEG2/faster_csv/tree/master/examples
For the example code to work, you should change:
require "faster_csv"
for
require "csv"
I'm trying to open a CSV file, look up a string, and then return the 2nd column of the csv file, but only the the first instance of it. I've gotten as far as the following, but unfortunately, it returns every instance. I'm a bit flummoxed.
Can the gods of Ruby help? Thanks much in advance.
M
for the purpose of this example, let's say names.csv is a file with the following:
foo, happy
foo, sad
bar, tired
foo, hungry
foo, bad
#!/usr/local/bin/ruby -w
require 'rubygems'
require 'fastercsv'
require 'pp'
FasterCSV.open('newfile.csv', 'w') do |output|
FasterCSV.foreach('names.csv') do |lookup|
index_PL = lookup.index('foo')
if index_PL
output << lookup[2]
end
end
end
ok, so, if I want to return all instances of foo, but in a csv, then how does that work?
so what I'd like as an outcome is happy, sad, hungry, bad. I thought it would be:
FasterCSV.open('newfile.csv', 'w') do |output|
FasterCSV.foreach('names.csv') do |lookup|
index_PL = lookup.index('foo')
if index_PL
build_str << "," << lookup[2]
end
output << build_str
end
end
but it does not seem to work
Replace foreach with open (to get an Enumerable) and find:
FasterCSV.open('newfile.csv', 'w') do |output|
output << FasterCSV.open('names.csv').find { |r| r.index('foo') }[2]
end
The index call will return nil if it doesn't find anything; that means that the find will give you the first row that has 'foo' and you can pull out the column at index 2 from the result.
If you're not certain that names.csv will have what you're looking for then a bit of error checking would be advisable:
FasterCSV.open('newfile.csv', 'w') do |output|
foos_row = FasterCSV.open('names.csv').find { |r| r.index('foo') }
if(foos_row)
output << foos_row[2]
else
# complain or something
end
end
Or, if you want to silently ignore the lack of 'foo' and use an empty string instead, you could do something like this:
FasterCSV.open('newfile.csv', 'w') do |output|
output << (FasterCSV.open('names.csv').find { |r| r.index('foo') } || ['','',''])[2]
end
I'd probably go with the "complain if it isn't found" version though.
I'm trying to query a table, fetch all records, and save the result as a CSV file.
This is what I've done so far:
require 'OCI8'
conn = OCI8.new('scott','tiger','020')
file = File.open('output.csv','w') do |f|
conn.exec('select * from emp') do |e|
f.write log.join(',')
end
end
.. And while it does generate a CSV file, the problem is that all records get saved onto a single line. How can I put the data such that each record goes onto a new line ?
Well, you can use f.puts instead of f.write there, but I'd recommend you take a look at CSV module:
http://ruby-doc.org/stdlib/libdoc/csv/rdoc/index.html
outfile = File.open('csvout', 'wb')
CSV::Writer.generate(outfile) do |csv|
csv << ['c1', nil, '', '"', "\r\n", 'c2']
...
end
outfile.close
PS: Actually, there is another CSV library called FasterCSV, which became CSV in standard library in Ruby 1.9. But in general, any should be better than writing it yourself.