I am trying to fix the width of the written text going to my .txt file.
Currently the values are collected through a gets command from user input. Then they are passed through a class object and assigned to various #___ variables. Then called under a Grade_Log.new(add_class, add_assignment, add_grade). And eventually written individually to the .txt file.
class Grade_Log
attr_accessor :which_class, :assignment_type, :grade
def initialize(which_class, assignment_type, grade)
#which_class = which_class
#assignment_type = assignment_type
#grade = grade
end
def attribute_class
#which_class
end
def attribute_assignment
#assignment_type
end
def attribute_grade
#grade
end
end
input = Grade_Log.new(add_class, add_assignment, add_grade)
File.open("grade_log.txt", "a") do |file|
file.write(input.attribute_class)
file.write(" ")
file.write(input.attribute_assignment)
file.write(" ")
file.write(input.attribute_grade)
file.write("\n")
end
I am getting the output that I am intending to get... "PHYSICS HOMEWORK 97" however, I would like for the spacing to be fixed at 20 width for each variable so I don't have to manually insert the " ".
I am working on a CLI Project and trying to open up a web page by using url variable declared in another method.
def self.open_deal_page(input)
index = input.to_i - 1
#deals = PopularDeals::NewDeals.new_deals
#deals.each do |info|
d = info[index]
#product_url = "#{d.url}"
end
#product_url.to_s
puts "They got me!"
end
def self.deal_page(product_url)
#self.open_deal_page(input)
deal = {}
html = Nokogiri::HTML(open(#product_url))
doc = Nokogiri::HTML(html)
deal[:name] = doc.css(".dealTitle h1").text.strip
deal[:discription] = doc.css(".textDescription").text.strip
deal[:purchase] = doc.css("div a.button").attribute("href")
deal
#binding.pry
end
but I am receiving this error.
`open': no implicit conversion of nil into String (TypeError)
any possible solution? Thank you so much in advance.
Try returning your #product_url within your open_deal_page method, because now you're returning puts "They got me!", and also note that your product_url is being created inside your each block, so, it won't be accessible then, try creating it before as an empty string and then you can return it.
def open_deal_page(input)
...
# Create the variable
product_url = ''
# Assign it the value
deals.each do |info|
product_url = "#{info[index].url}"
end
# And return it
product_url
end
In your deal_page method tell to Nokogiri to open the product_url that you're passing as argument.
def deal_page(product_url)
...
html = Nokogiri::HTML(open(product_url))
...
end
I have .csv file with rows of which every row represents one call with certain duration, number etc. I need to create array of Call objects - every Call.new expects Hash of parameters, so it's easy - it just takes rows from CSV. But for some reason it doesn't work - when I invoke Call.new(raw_call) it's nil.
It's also impossible for me to see any output - I placed puts in various places in code (inside blocks etc) and it simply doesn't show anything. I obviously have another class - Call, which holds initialize for Call etc.
require 'csv'
class CSVCallParser
attr_accessor :io
def initialize(io)
self.io = io
end
NAMES = {
a: :date,
b: :service,
c: :phone_number,
d: :duration,
e: :unit,
f: :cost
}
def run
parse do |raw_call|
parse_call(raw_call)
end
end
private
def parse_call(raw_call)
NAMES.each_with_object({}) do |name, title, memo|
memo[name] = raw_call[title.to_s]
end
end
def parse(&block)
CSV.parse(io, headers: true, header_converters: :symbol, &block)
end
end
CSVCallParser.new(ARGV[0]).run
Small sample of my .csv file: headers and one row:
"a","b","c","d","e","f"
"01.09.2016 08:49","International","48627843111","0:29","","0,00"
I noticed a few things that isn't going as expected. In the parse_call method,
def parse_call(raw_call)
NAMES.each_with_object({}) do |name, title, memo|
memo[name] = raw_call[title.to_s]
end
end
I tried to print name, title, and memo. I expected to get :a, :date, and {}, but what I actually got was [:a,:date],{}, and nil.
Also, raw_call headers are :a,:b,:c..., not :date, :service..., so you should be using raw_call[name], and converting that to string will not help, since the key is a symbol in the raw_call.
So I modified the function to
def parse_call(raw_call)
NAMES.each_with_object({}) do |name_title, memo|
memo[name_title[1]] = raw_call[name_title[0]]
end
end
name_title[1] returns the title (:date, :service, etc)
name_title[0] returns the name (:a, :b, etc)
Also, in this method
def run
parse do |raw_call|
parse_call(raw_call)
end
end
You are not returning any results you get, so you are getting nil,
So, I changed it to
def run
res = []
parse do |raw_call|
res << parse_call(raw_call)
end
res
end
Now, if I output the line
p CSVCallParser.new(File.read("file1.csv")).run
I get (I added two more lines to the csv sample)
[{:date=>"01.09.2016 08:49", :service=>"International", :phone_number=>"48627843111", :duration=>"0:29", :unit=>"", :cost=>"0,00"},
{:date=>"02.09.2016 08:49", :service=>"International", :phone_number=>"48622454111", :duration=>"1:29", :unit=>"", :cost=>"0,00"},
{:date=>"03.09.2016 08:49", :service=>"Domestic", :phone_number=>"48627843111", :duration=>"0:29", :unit=>"", :cost=>"0,00"}]
If you want to run this program from the terminal like so
ruby csv_call_parser.rb calls.csv
(In this case, calls.csv is passed in as an argument to ARGV)
You can do so by modifying the last line of the ruby file.
p CSVCallParser.new(File.read(ARGV[0])).run
This will also return the array with hashes like before.
csv = CSV.parse(csv_text, :headers => true)
puts csv.map(&:to_h)
outputs:
[{a:1, b:1}, {a:2, b:2}]
I am new to ruby and make a lot of mistakes, so I hope people who are experienced in ruby can share a bit of knowledge.
I can't figure out how I can make ruby save the text into a txt file that a method all writes.
class generator
def all
puts "i want to save this text into a txt file"
end
end
new_gen = generator.new
new_gen.all
my_file = File.new("Story.txt", "a+")
my_file.puts("all")
my_file.puts("\n")
my_file.close
I tried everything, but the txt file either has the "all" in it or it's completely blank. Any ideas? I also tried my_file.puts(all) and my_file.puts(new_gen.all).
If you want Generator to do the writing you could pass it an IO object.
class Generator
def initialize(io)
#io = io
end
def all
#io.puts "i want to save this text into a txt file"
end
end
# write to STDOUT
gen = Generator.new(STDOUT)
gen.all
# write to file
File.open("Story.txt", "a+") do |file|
gen = Generator.new(file)
gen.all
end
You method should simply return a string. Puts displays the string, does not return it. So change the class to:
class generator
def all
"i want to save this text into a txt file" # optionally add a return
end
end
new_gen = generator.new
new_gen.all
Then use the last version you tried: my_file.puts(new_gen.all)
Try this:
class Generator
def all
"i want to save this text into a txt file"
end
end
gen = Generator.new
f = File.new("Story.txt", "a+")
f.puts gen.all
f.close
I try to use the ruby standard csv lib to dump out the arr of object to a csv.file , called 'a.csv'
http://ruby-doc.org/stdlib-1.9.3/libdoc/csv/rdoc/CSV.html#method-c-dump
dump(ary_of_objs, io = "", options = Hash.new)
but in this method, how can i dump into a file?
there is no such examples exists and help. I google it no example to do for me...
Also, the docs said that...
The next method you can provide is an instance method called
csv_headers(). This method is expected to return the second line of
the document (again as an Array), which is to be used to give each
column a header. By default, ::load will set an instance variable if
the field header starts with an # character or call send() passing the
header as the method name and the field value as an argument. This
method is only called on the first object of the Array.
Anyone knows how to pass the instance method csv_headers() to this dump function?
I haven't tested this out yet, but it looks like io should be set to a file. According to the doc you linked "The io parameter can be used to serialize to a File"
Something like:
f = File.open("filename")
dump(ary_of_objs, io = f, options = Hash.new)
The accepted answer doesn't really answer the question so I thought I'd give a useful example.
First of all if you look at the docs at http://ruby-doc.org/stdlib-1.9.3/libdoc/csv/rdoc/CSV.html, if you hover over the method name for dump you see you can click to show source. If you do that you'll see that the dump method attempts to call csv_headers on the first object you pass in from ary_of_objs:
obj_template = ary_of_objs.first
...snip...
headers = obj_template.csv_headers
Then later you see that the method will call csv_dump on each object in ary_of_objs and pass in the headers:
ary_of_objs.each do |obj|
begin
csv << obj.csv_dump(headers)
rescue NoMethodError
csv << headers.map do |var|
if var[0] == #
obj.instance_variable_get(var)
else
obj[var[0..-2]]
end
end
end
end
So we need to augment each entry in array_of_objs to respond to those two methods. Here's an example wrapper class that would take a Hash, and return the hash keys as the CSV headers and then be able to dump each row based on the headers.
class CsvRowDump
def initialize(row_hash)
#row = row_hash
end
def csv_headers
#row.keys
end
def csv_dump(headers)
headers.map { |h| #row[h] }
end
end
There's one more catch though. This dump method wants to write an extra line at the top of the CSV file before the headers, and there's no way to skip that if you call this method due to this code at the top:
# write meta information
begin
csv << obj_template.class.csv_meta
rescue NoMethodError
csv << [:class, obj_template.class]
end
Even if you return '' from CsvRowDump.csv_meta that will still be a blank line where a parse expects the headers. So instead lets let dump write that line and then remove it afterwards when we call dump. This example assumes you have an array of hashes that all have the same keys (which will be the CSV header).
#rows = #hashes.map { |h| CsvRowDump.new(h) }
File.open(#filename, "wb") do |f|
str = CSV::dump(#rows)
f.write(str.split(/\n/)[1..-1].join("\n"))
end