I am trying to use the Yahoo Finance Gem, but am not able to get the information I want. When I try to get a quote, it creates a hash, but instead of the individual information (which I am trying to get), it gives a string will all the information in it. Is there a way to receive a single bit of information (such as % change) as a number? I am very new to ruby, so any help would be awesome.
require 'yahoofinance'
YahooFinance.get_quotes(YahooFinance::StandardQuote, 'yhoo') {|i|
puts i.change
puts i.changePoints
puts i.changePercent
puts i.time
}
Prints for me:
-0.03 - -0.17%
-0.03
-0.17
10:55am
or
r = yahooFinance.get_quotes(YahooFinance::StandardQuote, 'yhoo')
puts r[r.keys[0]].dayHigh
puts r["YHOO"].dayHigh
prints:
17.43
17.43
YahooFinance.get_quotes return a hash in which quote symbols are keys, and all data for each quote is a value. See YahooFinance::BaseQuote class to guess why it is possible to use getters like dayHigh() to auto parse data from the hash value.
I'm running Rails 3.2.8 along with the Ruby 1.9.3 and was having some problems with this gem.
So I just went straight to the source code and took that one file (its just a single file, and short too) and placed it in my /lib folder. In case you haven't been using your lib folder, you must add something like config.autoload_paths += Dir["#{config.root}/lib/**/"] to config/application.rb in order to load up lib folder classes from the rail console or elsewhere in rails.
Besides, its probably the simplest source code you will find and its always good to start reading the actual source that you rely on every day.
Related
I'm trying to grab some data from last.fm and use it in a simple sinatra app. I've worked out how to open the document but having issues extracting the data in ruby here is the first list of the API data I'd like to grab the name:
{"similarartists":{"artist":[{"name":"Sonny & Cher"}]}
This is just an extract of the return, I'm using this in my rb file:
require 'json'
require 'open-uri'
data = JSON.parse(open("http://ws.audioscrobbler.com/2.0/?method=artist.getsimilar&artist=editors&api_key=xxx&format=json").read)
puts data["similarartists"]["artist"]["name"]
It doesn't seem to be working I get can't convert String into Integer (TypeError) on ruby 1.9.3 but the name in the JSON isn't an integer? If I just put the following:
puts data["similarartists"]["artist"]
It returns the whole thing, but I want to grab inside of that and get the name.
"name"=>"Interpol"
I don't understand why it would complain about integers when the name is a string? Hope someone can help me!
Based on the comments thread, the issue is a misunderstanding of the structure of the data returned from the API call.
The exact issue was the structure had an array of artists under the artist key so to get at the name you need to do:
data['similarartists']['artist'][0]['name']
Note though that you should only do that if you are sure there will only be one artist. The nature of the return data suggests that won't always be the case so you might be better off pulling all names depending on your use doing something like:
data['similarartists']['artist'].map {|a| a['name']}.join(',')
That will join all of the artist names together comma separated.
In the future, you can track this issue down by looking at the full structure of the return data and making sure you see the correct structure. The docs on the API may indicate some help here too.
You also might check if someone has made a gem for accessing the API. Often a gem will up-level some of this raw output and give you a nice object to work with. I suggest searching GitHub for a last.fm gem.
The problem is that you are trying to access an Array with the index "name", Ruby tries to convert this to an Integer and fails which results in the Error message you are seeing.
If you test the class of data["similarartists"]["artist"].class you will see that it returns Array. So basically what is happening is that the JSON.parse() called created as the value of data["similarartists"]["artist"] an Array of Hashes. To access all of the artist names you can simply iterate through this array:
require 'json'
require 'open-uri'
data = JSON.parse(open("http://ws.audioscrobbler.com/2.0/?method=artist.getsimilar&artist=editors&api_key=29da5a0e01ca2d1524cac596d5462d67&format=jso\
n").read)
# iterate through the Array of returned artists and print their names
data["similarartists"]["artist"].each do |artist|
puts artist["name"]
end
# output
# Interpol
# White Lies
# The Cinematics
# Smith & Burrows
# The National
# Julian Plenti
# She Wants Revenge
# etc ...
If you only want the first entry for Interpol you can just use index [0]:
puts data["similarartists"]["artist"][0]["name"]
I'd like to get a word list from a text file using Ruby. I found how to use regex to parse only words here, so I made a script like following:
src = File.open("text.txt")
word_list = []
src.each do |line|
word_list << line.downcase.split(/[^[:alpha:]]/).delete_if {|x| x == ""}
end
word_list.flatten!.uniq!.sort!
p word_list
And the following is a sample text file text.txt:
TextMate may be the latest craze for developing Ruby on Rails
applications, but Vim is forever. This plugin offers the following
features for Ruby on Rails application development.
Automatically detects buffers containing files from Rails applications, and applies settings to those buffers (and only those
buffers). You can use an autocommand to apply your own custom
settings as well.
Unintrusive. Only files in a Rails application should be affected; regular Ruby scripts are left untouched. Even when enabled, the
plugin should keep out of your way if you're not using its features.
Easy navigation of the Rails directory structure. gf considers context and knows about partials, fixtures, and much more. There are
two commands, :A (alternate) and :R (related) for easy jumping between
files, including favorites like model to migration, template to
helper, and controller to functional test. For more advanced usage,
:Rmodel, :Rview, :Rcontroller, and several other commands are
provided.
As a Ruby novice, I'd like to learn better (more clear, concise, and following conventions) solutions for this problem.
Thanks for any advices and corrections.
A more idiomatic code would be:
word_list = open("text.txt")
.lines
.flat_map { |line| line.downcase.split(/[^[:alpha:]]/).reject(&:empty?) }
.uniq
.sort
# I suppose you want each line and collect the results
word_list = File.open("text.txt").each_line.collect do |line|
# collecting is done via collect above, no need anymore
# .reject(&:empty?) calls .empty? on each element
line.downcase.split(/[^[:alpha:]]/).reject(&:empty?)
# you can chain on blocks as well
end.flatten!.uniq!.sort!
p word_list
I'm having an awful time trying to use a library to parse an XML File into a hash like object, modify it, then print it back out to another XML file in Ruby. For a class I'm taking, we're supposed to use a Java JAXB like library where we convert XML into an object. We've already done SAX and DOM methods so we can't use those methods of XML de-serialization. Nokogiri helped me with both of these in Ruby.
The only problem is that besides the SIMPLE modifications I'm making to the objects, when I write to file it has drastic differences. Is there a Ruby library meant for doing just this? I've tried: ROXML, XML::Mapping, and ActiveSupport::CoreExt. The only one I can get to even run is ActiveSupport, and even then it starts putting element attributes as child elements in the output XML.
I'm willing to try out XmlSimple, but I'm curious has anyone actually had to do this before/run into the same problems? Again, I can't read in lines one at a time like SAX or build a Tree like structure like DOM, it needs to be a hash like object.
Any help is much appreciated!
You should have a look into nokogiri: http://nokogiri.org/
Then you can parse the XML like this :
xml_file = "some_path"
#xml = Nokogiri::XML(File.open xml_file)
#xml.xpath('//listing').each do |node|
style = node.search("style").text
end
With Xpath, you can perform queries in the XML :
#xml.xpath("//listing[name='John']").first(10)
OK, I got it working. After looking at ActiveSupport::CoreExt 's source code I found it just uses a gem called xml-simple. What's obnoxious is the gem, library name in the require statement, and class name are a mixture of hyphenated and non hyphenated spellings. For future reference here's what I did:
# gem install xml-simple
# ^ all lowercase, hyphenated
require 'xmlsimple'
# ^ all lowercase, not hyphenated
doc = XmlSimple.xml_in 'hw3.xml', 'KeepRoot' => true
# ^ Camel cased (it's a class), not hyphenated
# doc.class => Hash
# manipulate doc as a hash
file = File.new('HW3a.xml', 'w')
file.write("<?xml version='1.0' encoding='utf-8'?>\n")
file.write(XmlSimple.xml_out doc, 'KeepRoot' => true)
I hope this helps someone. Also make sure you pay attention to case and hyphens with this gem!!!
I'm using Ruby 1.8.7's RSS::Parser, part of stdlib. I'm new to Ruby.
I want to parse an RSS feed, make some changes to the data, then output it (as RSS).
The docs say I can use '#to_s', but and it seems to work with some feeds, but not others.
This works:
#!/usr/bin/ruby -w
require 'rss'
require 'net/http'
url = 'http://news.ycombinator.com/rss'
feed = Net::HTTP.get_response(URI.parse(url)).body
rss = RSS::Parser.parse(feed, false, true)
# Here I would make some changes to the RSS, but right now I'm not.
p rss.to_s
Returns expected output: XML text.
This fails:
#!/usr/bin/ruby -w
require 'rss'
require 'net/http'
url = 'http://feeds.feedburner.com/devourfeed'
feed = Net::HTTP.get_response(URI.parse(url)).body
rss = RSS::Parser.parse(feed, false, true)
# Here I would make some changes to the RSS, but right now I'm not.
p rss.to_s
Returns nothing (empty quotes).
And yet, if I change the last line to:
p rss
I can see that the object is filled with all of the feed data. It's the to_s method that fails.
Why?
How can I get some kind of error output to debug a problem like this?
From what I can tell, the problem isn't in to_s, it's in the parser itself. Stepping way into the parser.rb code showed nothing being returned, so to_s returning an empty string is valid.
I'd recommend looking at something like Feedzirra.
Also, as a FYI, take a look at Ruby's Open::URI module for easy retrieval of web assets, like feeds. Open-URI is simple but adequate for most tasks. Net::HTTP is lower level, which will require you to type a lot more code to replace the functionality of Open-URI.
I had the same problem, so I started debugging the code. I think the ruby rss has a few too many required elements. The channel need to have "title, link, description", if one is missing to_s will fail.
The second feed in the example above is missing the description, which will make the to_s fail...
I believe this is a bug, but I really don't understand the code and barely ruby so who knows. It would seem natural to me that to_s would try its best even if some elements are missing.
Either way
rss.channel.description="something"
rss.to_s
will "work"
The problem lies in def have_required_elements?
Or in the
self.class::MODELS
So, I wrote a simple Ruby class, and put it in my rails /lib directory. This class has the following method:
def Image.make_specific_image(paths, newfilename)
puts "making specific image"
#new_image = File.open(newfilename, "w")
puts #new_image.inspect
##blank.each(">") do |line|
puts line + "~~~~~"
#new_image.puts line
if line =~ /<g/
paths.each do |p|
puts "adding a path"
puts p
#new_image.puts p
end
end
end
end
Which creates a new file, and copies a hardcoded string (##blank) to this file, adding custom content at a certain location (after a g tag is found).
If I run this code from ruby, everything is just peachy.
HOWEVER, if I run this code from rails, the file gets CREATED, but is then empty. I've inspected each line of the code: nothing I'm trying to write to the file is nil, but the file is empty nonetheless.
I'm really stumped here. Is it a permissions thing? If so, why on EARTH would Rails have the permissions necessary to MAKE a file, but then not WRITE to the file it made?
Does File I/O somehow work differently in rails?
Specifically, I have a model method that calls:
Image.make_specific_image(paths, creature.id.to_s + ".svg")
which succesfully makes a file of the type "47.svg" that is empty.
Have you tried calling close on the file after you're done writing it? (You could also use the block-based File.open syntax, which will automatically close once the block is complete). I'm guessing the problem is that the writes aren't getting flushed to disk.
So.
Apparently File I/0 DOES work in Rails...just very, very slowly. In Ruby, as soon as I go to look at the file, it's there, it works, everything is spiffy.
Before, after seeing blank files from Rails, I would get frustrated, then delete the file, and change some code and try again (so as not to be full of spam, since each file is genearted on creature creation, so I would soon end up with a lot of files like "47.svg" and "48.svg", etc.
....So. I took my lunch break, came back to see if I could tell if the permissions of the rails generated file were different from the ruby generated file...and noticed that the RAILS file is no longer blank.
Seems to take about five minutes for rails to finally write to the file, even AFTER it claims it's done processing that whole call. Ruby takes a few seconds. Not really sure WHY they are so different, but at least now I know it's not a permissions thing.
Edit: Actually, on some files take so long, others are instant...