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
Related
In ruby, if I have a CSV like this:
make,model,color,doors,email
dodge,charger,black,4,practice1#whatever.com
ford,focus,blue,5,practice2#whatever.com
nissan,350z,black,2,practice3#whatever.com
mazda,miata,white,2,practice4#whatever.com
honda,civid,brown,4,practice5#whatever.com
corvette,stingray,red,2,practice6#whatever.com
ford,fiesta,blue,5,practice7#whatever.com
bmw,m4,black,2,practice8#whatever.com
audi,a5,blue,2,practice9#whatever.com
subaru,brz,black,2,practice10#whatever.com
lexus,rc,black,2,practice11#whatever.com
I want to allow a user to enter an email and be able to edit any one of the options listed. For example, a user enters the email "practice11#whatever.com" and it will output "lexus,rc,black,2,practice11#whatever.com". Then from here the program will output some message that will tell the user to select to edit by "make,model,color,doors,email", and then be able to change whatever is there. Like lets say they choose "color", then they can change the color from "black" to "blue" of "practice11#whatever.com" line. I believe this can be done using a hash and using key-values but I am not sure how to exactly make the editing part work.
this is my current code:
require "csv"
csv = CSV.read('cars.csv', headers: true)
demo = gets.chomp
print csv.find {|row| row['email'] == demo}
all it does it takes in the csv file and allows a user to enter in an email and it will output that specific line.
So - your question is a bit vague and involves a number of implied questions, such as "how do I write code that can ask for different options and act accordingly" - so it might help if you clarify exactly what you are trying to ask.
From the looks of it, you seem most interested in understanding how to modify the CSV table, and to get info about the CSV fields/table/data etc..
And for this, you have two friends: The ruby 'p' method and the docs.
The 'p' method allows you to inspect objects. "p someObject" is the same as calling 'puts someObject.inspect' - and it's very handy, as is "puts someObject.class" to find out what type of object you're dealing with.
In this case, you can change the last line of your code a bit to get some info:
puts csv.class
got = csv.find {|row| row['email'] == demo}
p got
And suddenly we learn we are dealing with a CSV::Table
This is not surprising, let's head over to the docs. I don't know what version of ruby you're using, but 2.6.1 is current enough to have the info we need and is plenty old at this point, so you probably have access to it:
https://ruby-doc.org/stdlib-2.6.1/libdoc/csv/rdoc/CSV.html
Tells us that if we do the CSV.read using headers:
"If headers specified, reading methods return an instance of CSV::Table, consisting of CSV::Row."
So now we know we have a CSV::Table (which is much like an array/list but with some convenience methods (such as the 'find' that you are using).
And a CSV::Row is basically a hash that maintains it's order and is, as expected, keyed according to the headers.
So we can do:
p got.fields
p got['model']
got['model'] = 'edsel'
p got['model']
p got.fields
And not surprisingly, the CSV::Table has a 'to_s' method that let's us print out the CSV:
puts csv.to_s
You can probably take it from here.
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
I am still fairly new to Ruby and to databases in general, and am trying to better learn how to use the two together. I have browsed through several online tutorials but haven't been able to figure a few things out. I am working with PostgreSQL and am simply trying to read the data in my database and manipulate in some way the data contained in the actual cell. From a tutorial I have the following functions:
def queryUserTable
#conn.exec( "SELECT * FROM users" ) do |result|
result.each do |row|
yield row if block_given?
end
end
end
and a simple way to print out the information in the rows would be something like
p.queryUserTable {|row| printf("%s %s\n", row['first_name'], row['last_name'])}
(with p being the connection). However all this is doing it printing out each value in the row and column specified as a whole, then continuing to the next row. What I would like to know is how I can grab for instance the value in row 1 under column first name and use it for something else? From what I understand, it looks like the rows are hashes and so I should be able to do something similar to {|row, value| #my_var = value } but I get no results by doing so, so I am not understanding how this all works properly. I am hoping someone can better explain how this works. Hope that makes sense. Thanks!
EDIT:
Does it have anything to do with this line in my function?:
result.each do |row| #do I need to add |row,value| here as well?
Is there a reason you're not using an ORM like ActiveRecord? Although it certainly has some downsides, it may well be helpful for someone who is new to databases and ruby. If you want a tutorial on active record and rails, I highly recommend Michael Hartl's awesome free tutorial[1].
I'm not exactly sure what you're trying to do, but I can correct a couple of misconceptions. First of all, result is not a hash - it is an array of hashes. That is why doing result.each { |row, value| ... doesn't initialize value. Once you have an individual row, you can do row.each { |col_name, val| ...
Second, if you want to grab a value from a specific row, you should specify the row in the query. You must know something about the row you want information about. For getting the user with id = 1, for instance:
user = #conn.exec("SELECT first_name FROM users WHERE id = 1").first
unless user.nil?
# do something with user["first_name"]
If you were to use activerecord, you could just do
user = User.findById(1)
I would not want to set the value in the queryUserTable loop, because it will get set on each loop, and just retain the value of the last time it executes.
[1] https://www.railstutorial.org/book
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