I am playing around with the Red Hat Satellite API. One of the values being returned for an API call is dateTime.iso8601 "last_checkin" - Last time server successfully checked in. I'm not sure how to parse this, though.
This is the code that returns the data:
systems.each do |system|
print "#{system["name"]}" + " " + "#{system["last_checkin"]}" + "\n"
end
It gives a hash back: #<XMLRPC::DateTime:0x97102d8>. At least, I think that's a hash.
What do I need to do to look inside it and extract useful information?
That’s not a Hash, that’s an instance of class XMLRPC::DateTime. Use it’s methods to get printable values, e.g.:
systems.each do |system|
system = system["last_checkin"] # or whatever value you are interested in
puts "#{system.mon}-#{system.day}-#{system.year}"
end
Also please avoid using "a"+"b" string concatenation; there is inplace-evaluation ruby paradigm for that ("#{val}".)
Related
Here is what I currently have; the only problem being the external file loads without the placeholder text updated -- instead rather, the placeholder text just says '[NOUN]' instead of actual noun inserted from user in earlier program prompt.
Update; cleaned up with #tadmans suggestions, it is however, still not passing user input to placeholder text in external .txt file.
puts "\n\nOnce upon a time on the internet... \n\n"
puts "Name 1 website:"
print "1. "
loc=gets
puts "\n\Write 5 adjectives: "
print "1. "
adj1=gets
print "\n2. "
adj2=gets
print "\n3. "
adj3=gets
print "\n4. "
adj4=gets
print "\n5. "
adj5=gets
puts "\n\Write 2 nouns: "
print "1. "
noun1=gets
print "\n2. "
noun2=gets
puts "\n\nWrite 1 verb: "
print "1. "
verb=gets
puts "\n\nWrite 1 adverb: "
print "1. "
ptverb=gets
string_story = File.read("dynamicstory.txt")
puts string_story
Currently output is (i.e. placeholders not populated):
\n\nOnce upon a time on the internet...\n\n
One dreary evening while browsing the #{loc} website online, I stumbled accross a #{adj1} Frog creature named Earl. This frog would sit perturbed for hours at a time at the corner of my screen like Malware. One day, the frog appeared with a #{adj2} companion named Waldo that sat on the other corner of my screen. He had a #{adj3} set of ears with sharp #{noun1} inside. As the internet frogs began conversing and becoming close friends in hopes of #{noun2}, they eventually created a generic start-up together. They knew their start-up was #{adj4} but didn't seem to care and pushed through anyway. They would #{verb} on the beach with each other in the evenings after operating with shady ethics by day. They could only dream of a shiny and #{adj5} future full of gold. But then they eventually #{ptverb} and moved to Canada.\n\n
The End\n\n\n
It's important to note that the Ruby string interpolation syntax is only valid within actual Ruby code, and it does not apply in external files. Those are just plain strings.
If you want to do rough interpolation on those you'll need to restructure your program in order to make it easy to do. The last thing you want is to have to eval that string.
When writing code, always think about breaking up your program into methods or functions that have a specific function and can be used in a variety of situations. Ruby generally encourages code-reuse and promoting the "DRY principle", or "Don't Repeat Yourself".
For example, your input method boils down to this generic method:
def input(thing, count = 1)
puts "Name %d %s:" % [ count, thing ]
count.times.map do |i|
print '%d. ' % (i + 1)
gets.chomp
end
end
Where that gets input for a random thing with an arbitrary count. I'm using sprintf-style formatters here with % but you're free to use regular interpolation if that's how you like it. I just find it leads to a less cluttered string, especially when interpolating complicated chunks of code.
Next you need to organize that data into a proper container so you can access it programmatically. Using a bunch of unrelated variables is problematic. Using a Hash here makes it easy:
puts "\n\nOnce upon a time on the internet... \n\n"
words = { }
words[:website] = input('website')
words[:adjective] = input('adjectives', 5)
words[:noun] = input('nouns', 2)
words[:verb] = input('verb')
words[:adverb] = input('adverb')
Notice how you can now alter the order of these things by re-ordering the lines of code, and you can change how many of something you ask for by adjusting a single number, very easy.
The next thing to fix is your interpolation problem. Instead of using Ruby notation #{...}, which is hard to evaluate, go with something simple. In this case %verb1 and %noun2 are used:
def interpolate(string, values)
string.gsub(/\%(website|adjective|noun|verb|adverb)(\d+)/) do
values.dig($1.to_sym, $2.to_i - 1)
end
end
That looks a bit ugly, but the regular expression is used to identify those tags and $1 and $2 pull out the two parts, word and number, separately, based on the capturing done in the regular expression. This might look a bit advanced, but if you take the time to understand this method you can very quickly solve fairly complicated problems with little fuss. It's something you'll use in a lot of situations when parsing or rewriting strings.
Here's a quick way to test it:
string_story = File.read("dynamicstory.txt")
puts interpolate(string_story, words)
Where the content of your file looks like:
One dreary evening while browsing the %website1 website online,
I stumbled accross a %adjective1 Frog creature named Earl.
You could also adjust your interpolate method to pick random words.
I'm parsing a very large json output from an application API and end up with a ruby array similar to the sanitized version below:
{"log_entries"=>
[{"id=>"SDF888B2B2KAZZ0AGGB200",
"type"=>"warning",
"summary"=>"Things happened",
"created"=>"2017-07-11T18:40:31Z",
"person"=>
{"id"=>"44bAN8",
"name"=>"Harry"}
"system"=>"local",
"service"=>"syslog"
{"id=>"HMB001NBALLB81MMLLABLK",
"type"=>"info",
"summary"=>"Notice",
"created"=>"2017-06-02T11:23:21Z",
"person"=>
{"id"=>"372z1j",
"name"=>"Sally"}
"system"=>"local",
"service"=>"syslog"}]},
"other"=>200,
"set"=>0,
"more"=>false,
"total"=nil}
I just need to be able to print the value of the "created" key only in the first block. Meaning, when the program exits, I need it to print "2017-07-11T18:40:31Z." I've googled a lot but wasn't successful in finding anything. I've tried something like:
puts ["log_entries"]["id"]["created"]
My expectation was to print all of them to start somewhere and even that yields an error. Forgive me, I don't use ruby much.
Since log_entries is an array you can just access the first element and get its created value.
Assuming the variable result holds the whole hash (the JSON you parse from the API):
puts result['log_entries'][0]['created']
will print out the first date. Now you might want to guard that for cases where log_entries empty, so wrap it in a if:
if result['log_entries'].any?
puts result['log_entries'][0]['created']
end
Your json is not in valid format. But assuming you have the right format, following should work
result["log_entries"].collect{|entry| entry["created"]}
=> ["2017-07-11T18:40:31Z", "2017-06-02T11:23:21Z"]
Above code will collect all the created date and give you an array
While reading some data from the Twitter api, I inserted the data into the file like this
results.each do |f|
running_count += 1
myfile.puts "#{f.user_mentions}"
...
The results (2 sample lines below) look like this in the file
[#<Twitter::Entity::UserMention:0x007fda754035803485 #attrs={:screen_name=>"mr_blah_blah", :name=>"mr blah blah", :id=>2142450461, :id_str=>"2141354324324", :indices=>[3, 15]}>]
[#<Twitter::Entity::UserMention:0x007f490580928 #attrs={:screen_name=>"andrew_jackson", :name=>"Andy Jackson", :id=>1607sdfds, :id_str=>"16345435", :indices=>[3, 14]}>]
Since the only information I'm actually interested in is the :screen_name, I was wondering if there's a way that I could only insert the screen names into the file. Since each line is in array brackets and then I'm looking for the screen name inside the #attrs, I did this
myfile.puts "#{f.user_mentions[0]#attrs{"screen_name"}}"
This didn't work, and I didn't expect it to, as I'm not really sure if that's technically array etc. Can you suggest how it would be done?
You need to access the #attrs instance variable in the Twitter UserMention object. If you want to puts the screen name from the first object, based on your current output, I would write
myfile.puts "#{f.user_mentions[0].attrs[:screen_name]"
Also, putting the code on how results is returned would help get a definite answer quickly. Cheers!
Assuming that results is an array of Twitter::Entity::UserMention
results.each do |r|
myfile.puts r.screen_name
end
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'm downloading content from a webpage that seems to be in JSON. It is a large file with the following format:
"address1":"123 Street","address2":"Apt 1","city":"City","state":"ST","zip":"xxxxx","country":"US"
There are about 1000 of these entries, where each entry is contained within brackets. When I download the page using RestClient.get (open-uri for some reason was throwing a http 500 error), the data is in the following format:
\"address\1":\"123 Street\",\"address2\":\"Apt 1\",\"city\":\"City\",\"state\":\"ST\",\"zip\":\"xxxxx\",\"country\":\"US\"
When I then use the json class
parsed = JSON.parse(data_out)
it completely scrambles both the order of entries within the data structure, and also the order of the objects within each entry, for example:
"address1"=>"123 Street", "city"=>"City", "country"=>"US", "address2"=>"Apt 1"
If instead I use
data_j=data_out.to_json
then I get:
\\\"address\\\1":\\\"123 Street\\\",\\\"address2\\\":\\\"Apt 1\\\",\\\"city\\\":\\\"City\\\",\\\"state\\\":\\\"ST\\\",\\\"zip\\\":\\\"xxxxx\\\",\\\"country\\\":\\\"US\\\"
Further, only using the json class seems to allow me to select the entries I want:
parsed[1]["address1"]
=> "123 Street"
data_j[1]["address1"]
TypeError: can't convert String into Integer
from (irb):17:in `[]'
from (irb):17
from :0
Any idea whats going on? I guess since the json commands are working I can use them, but it is disconcerting that its scrambling the entries and order of the objects.
Although the data appears ordered in string form, it represents an unordered dataset. The line:
parsed = JSON.parse(data_out)
which you use is the correct way to convert the string form into something usable in Ruby. I cannot see the full structure from your example, so I don't know whether the top level is an array or id-based hash. I suspect the latter since you say it becomes unordered when you view from Ruby. Therefore, if you knew which part of the address you were interested in you might have code like this:
# Writes all the cities
parsed.each do |id,data|
puts data["city"]
end
If the outer structure is an array, you'd do this:
# Writes all the cities
parsed.each do |data|
puts data["city"]
end