I'm trying to sort in descending order an array of photo objects from Flickr API based on the number of comments(count_comments) of each photo. I'm using the following code.
def rank_photos(photos)
photos.sort_by { |photo| photo.count_comments * -1 }
end
However I get the following error message.
*': negative argument (ArgumentError)
Here is what the Array looks like
[{"id"=>"38280904752", "owner"=>"131718287#N07",
"secret"=>"abe0b93180", "server"=>"4583", "farm"=>5,
"title"=>"IMG_3640", "ispublic"=>1, "isfriend"=>0, "isfamily"=>0,
"count_comments"=>"0", "tags"=>"washington post dc web women codeher17
dctech tech technology",
"url_m"=>"https://farm5.staticflickr.com/4583/38280904752_abe0b93180.jpg", "height_m"=>"333", "width_m"=>"500"}, {"id"=>"38312540901",
"owner"=>"131718287#N07", "secret"=>"7b6e6805d4", "server"=>"4568",
"farm"=>5, "title"=>"IMG_3458", "ispublic"=>1, "isfriend"=>0,
"isfamily"=>0, "count_comments"=>"0", "tags"=>"washington post dc web
women codeher17 dctech tech technology",
"url_m"=>"https://farm5.staticflickr.com/4568/38312540901_7b6e6805d4.jpg", "height_m"=>"500", "width_m"=>"333"}, {"id"=>"38281453252",
"owner"=>"131718287#N07", "secret"=>"438293cffd", "server"=>"4539",
"farm"=>5, "title"=>"IMG_3460", "ispublic"=>1, "isfriend"=>0,
"isfamily"=>0, "count_comments"=>"0", "tags"=>"washington post dc web
women codeher17 dctech tech technology",
"url_m"=>"https://farm5.staticflickr.com/4539/38281453252_438293cffd.jpg", "height_m"=>"333", "width_m"=>"500"}
Why is throwing this error?
count_comments is a string, so you should convert it to a number first. In the process you can also eliminate the multiplication altogether.
def rank_photos(photos)
photos.sort_by { |photo| -photo.count_comments.to_i }
end
Related
I am trying to count the correct inputs from the user. An input looks like:
m = "<ex=1>test xxxx <ex=1>test xxxxx test <ex=1>"
The tag ex=1 and the word test have to be connected and in this particular order to count as correct. In case of an invalid input, I want to send the user an error message that explains the error.
I tried to do it as written below:
ex_test_size = m.scan(/<ex=1>test/).size # => 2
test_size = m.scan(/test/).size # => 3
ex_size = m.scan(/<ex=1>/).size # => 3
puts "lack of tags(<ex=1>)" if ex_test_size < ex_size
puts "Lack of the word(test)" if ex_test_size < test_size
I believe it can be written in a better way as the way I wrote, I guess, is prone to errors. How can I make sure that all the errors will be found and shown to the user?
You might use negative lookarounds:
#⇒ ["xxx test", "<ex=1>"]
m.scan(/<ex=1>(?!test).{,4}|.{,4}(?<!<ex=1>)test/).map do |msg|
"<ex=1>test expected, #{msg} got"
end.join(', ')
We scan the string for either <ex=1> not followed by test or vice versa. Also, we grab up to 4 characters that violate the rule for the more descriptive message.
I'm attempting to parse the following XML:
<marketstat><type id="18">
<buy><volume>33000000</volume><avg>40.53</avg><max>65.57</max><min>6.55</min><stddev>26.61</stddev><median>58.56</median><percentile>65.57</percentile></buy>
<sell><volume>494489</volume><avg>69.47</avg><max>69.47</max><min>69.47</min><stddev>0.00</stddev><median>69.47</median><percentile>69.47</percentile></sell>
<all><volume>33494489</volume><avg>40.96</avg><max>69.47</max><min>6.55</min><stddev>26.77</stddev><median>58.56</median><percentile>6.55</percentile></all>
</type><type id="19">
<buy><volume>270000</volume><avg>1707.31</avg><max>3549.38</max><min>239.74</min><stddev>1554.26</stddev><median>239.75</median><percentile>3549.34</percentile></buy>
<sell><volume>48599</volume><avg>24930.45</avg><max>29869.95</max><min>5200.00</min><stddev>9875.66</stddev><median>29869.93</median><percentile>5232.20</percentile></sell>
<all><volume>280926</volume><avg>1957.07</avg><max>10750.00</max><min>239.74</min><stddev>3352.87</stddev><median>1874.31</median><percentile>239.74</percentile></all>
</type></marketstat>
</evec_api>
The pieces of information that I want to retrieve are the minimum sell and maximum buy values, associated with the ID, found here: <sell><min>69.47</min></sell>.
I'm currently using the following to get the XML: marketData = Nokogiri::XML(open(api))
Use xpath to pull out the nodes of interest, then convert them to Floats and pick the value you want. The path to your minimum sell node is /marketstat/type/sell/min, or if you want to use shorthand, // says "anywhere in the document", so you can specify just //sell/min to get all of the minimum sell nodes and //buy/max to get all of the maximum buys.
sells = market_data.xpath('//sell/min').map(&:content).map(&:to_f)
buys = market_data.xpath('//buy/max').map(&:content).map(&:to_f)
puts sells.min, buys.max
The following will print the ID and its corresponding min/max:
marketData = Nokogiri::XML(open(api))
marketData.xpath("//type").each do |i|
puts "#{i.attr('id')}: #{i.xpath('.//max').map {|j| j.text.to_f}.max}"
puts "#{i.attr('id')}: #{i.xpath('.//min').map {|j| j.text.to_f}.min}"
end
Output:
18: 69.47
18: 6.55
19: 29869.95
19: 239.74
I am trying to map an enumerator coming the the Twitter API. I can successfully map the entire enumerable using test.map(&:attrs) and I can map specific fields however when I try to map the id_str field I get a undefined method error. I can't figure out if my syntax is off or if there are other considerations.
Below is my sample code and output:
print "original output\n"
print test.map(&:attrs)
print "\n\nmap a few fields\n"
print test.map { |e| { id: e.id,
name: e.name,
screen_name: e.screen_name
}}
print "\n\nid_str seems to return a undefined method\n"
print test.map { |e| { id: e.id,
id_str: e.id_str,
name: e.name,
screen_name: e.screen_name
}}
Generates the following output:
original output
[{:id=>78194111, :id_str=>"78194111", :name=>"Chelsea Peretti", :screen_name=>"ChelseaVPeretti", :location=>"Los Angeles", :description=>"One of the greats!", :url=>"http://t.co/3rRz8qGpeW", :entities=>{:url=>{:urls=>[{:url=>"http://t.co/3rRz8qGpeW", :expanded_url=>"http://www.chelseaperetti.com", :
display_url=>"chelseaperetti.com", :indices=>[0, 22]}]}, :description=>{:urls=>[]}}, :protected=>false, :followers_count=>249943, :friends_count=>740, :listed_count=>4277, :created_at=>"Tue Sep 29 02:35:35 +0000 2009", :favourites_count=>33016, :utc_offset=>-28800, :time_zone=>"Pacific Time (US & Ca
nada)", :geo_enabled=>true, :verified=>true, :statuses_count=>14958, :lang=>"en", :status=>{:created_at=>"Mon Dec 09 00:40:48 +0000 2013", :id=>409845047744409600, :id_str=>"409845047744409600", :text=>"Really looking forward to spending half my life in an apple store", :source=>"<a href=\"http://tw
itter.com/download/iphone\" rel=\"nofollow\">Twitter for iPhone</a>", :truncated=>false, :in_reply_to_status_id=>nil, :in_reply_to_status_id_str=>nil, :in_reply_to_user_id=>nil, :in_reply_to_user_id_str=>nil, :in_reply_to_screen_name=>nil, :geo=>nil, :coordinates=>nil, :place=>nil, :contributors=>ni
l, :retweet_count=>13, :favorite_count=>77, :entities=>{:hashtags=>[], :symbols=>[], :urls=>[], :user_mentions=>[]}, :favorited=>false, :retweeted=>false, :lang=>"en"}, :contributors_enabled=>false, :is_translator=>false, :profile_background_color=>"022330", :profile_background_image_url=>"http://a0
.twimg.com/profile_background_images/777102099/405580aee5a6a6d3f4d608b5bc488149.jpeg", :profile_background_image_url_https=>"https://si0.twimg.com/profile_background_images/777102099/405580aee5a6a6d3f4d608b5bc488149.jpeg", :profile_background_tile=>true, :profile_image_url=>"http://pbs.twimg.com/pro
file_images/378800000812827132/fe8566998e61c0f3e1275af4953a22e9_normal.jpeg", :profile_image_url_https=>"https://pbs.twimg.com/profile_images/378800000812827132/fe8566998e61c0f3e1275af4953a22e9_normal.jpeg", :profile_banner_url=>"https://pbs.twimg.com/profile_banners/78194111/1382904580", :profile_l
ink_color=>"0084B4", :profile_sidebar_border_color=>"FFFFFF", :profile_sidebar_fill_color=>"C0DFEC", :profile_text_color=>"333333", :profile_use_background_image=>true, :default_profile=>false, :default_profile_image=>false, :following=>false, :follow_request_sent=>false, :notifications=>false}]
map a few fields
[{:id=>78194111, :name=>"Chelsea Peretti", :screen_name=>"ChelseaVPeretti"}]
id_str seems to return a undefined method
C:/RailsInstaller/AppCode/first attempt at graph.rb:142:in `block in <main>': undefined method `id_str' for #<Twitter::User:0x2b602f0> (NoMethodError)
from C:/RailsInstaller/AppCode/first attempt at graph.rb:141:in `map'
from C:/RailsInstaller/AppCode/first attempt at graph.rb:141:in `<main>'
Pretty new to playing with the Twitter API in Ruby myself, but it turns out that id_str isn't a method on the Ruby Twitter::User objects you're trying to enumerate over. Running a quick check on a particular one, say, test.first.methods will confirm this.
This means you can't access id_str with dot notation. It is however a key to the hashes returned by test.map(&:attrs) so you could amend your above code by doing this:
print test.map { |e| { id: e.attrs[:id],
id_str: e.attrs[:id_str],
name: e.attrs[:name],
screen_name: e.attrs[:screen_name]
}}
If you are dead set on using dot notation, you could easily convert each hash object into an OpenStruct like this:
friends = test.map { |f| OpenStruct.new(f.attrs) }
Then you could simply do friends.map(&:id_str).
I think the confusion lies in your sample code above. In the first line, your output is an array of hashes. But what you are mapping over is an array of Twitter::User objects. The former has id_str as a key, but the latter does not have such a method.
I'm a Java guy, new to Ruby. I've been playing with it just to see what it can do, and I'm running into an issue that I can't solve.
I decided to try out Sinatra, again, just to see what it can do, and decided to play with the ESPN API and see if I can pull the venue of a team via the API.
I'm able to make the call and get the data back, but I am having trouble parsing it:
{"sports"=>[{"name"=>"baseball", "id"=>1, "uid"=>"s:1", "leagues"=>[{"name"=>"Major League Baseball", "abbreviation"=>"mlb", "id"=>10, "uid"=>"s:1~l:10", "groupId"=>9, "shortName"=>"MLB", "teams"=>[{"id"=>17, "uid"=>"s:1~l:10~t:17", "location"=>"Cincinnati", "name"=>"Reds", "abbreviation"=>"CIN", "color"=>"D60042", "venues"=>[{"id"=>83, "name"=>"Great American Ball Park", "city"=>"Cincinnati", "state"=>"Ohio", "country"=>"", "capacity"=>0}], "links"=>{"api"=>{"teams"=>{"href"=>"http://api.espn.com/v1/sports/baseball/mlb/teams/17"}, "news"=>{"href"=>"http://api.espn.com/v1/sports/baseball/mlb/teams/17/news"}, "notes"=>{"href"=>"http://api.espn.com/v1/sports/baseball/mlb/teams/17/news/notes"}}, "web"=>{"teams"=>{"href"=>"http://espn.go.com/mlb/team/_/name/cin/cincinnati-reds?ex_cid=espnapi_public"}}, "mobile"=>{"teams"=>{"href"=>"http://m.espn.go.com/mlb/clubhouse?teamId=17&ex_cid=espnapi_public"}}}}]}]}], "resultsOffset"=>0, "resultsLimit"=>50, "resultsCount"=>1, "timestamp"=>"2013-08-04T14:47:13Z", "status"=>"success"}
I want to pull the venues part of the object, specifically the name value. Every time I try to parse it I end up getting an error along the lines of "cannot change from nil to string" and then also I've gotten an integer to string error.
Here's what i have so far:
get '/venue/:team' do
id = ids[params[:team]]
url = 'http://api.espn.com/v1/sports/baseball/mlb/teams/' + id + '?enable=venues&apikey=' + $key
resp = Net::HTTP.get_response(URI.parse(url))
data = resp.body
parsed = JSON.parse(resp.body)
#venueData = parsed["sports"]
"Looking for the venue of the #{params[:team]}, which has id " + id + ", and here's the data returned: " + venueData.to_s
end
When I do parsed["sports"} I get:
[{"name"=>"baseball", "id"=>1, "uid"=>"s:1", "leagues"=>[{"name"=>"Major League Baseball", "abbreviation"=>"mlb", "id"=>10, "uid"=>"s:1~l:10", "groupId"=>9, "shortName"=>"MLB", "teams"=>[{"id"=>17, "uid"=>"s:1~l:10~t:17", "location"=>"Cincinnati", "name"=>"Reds", "abbreviation"=>"CIN", "color"=>"D60042", "venues"=>[{"id"=>83, "name"=>"Great American Ball Park", "city"=>"Cincinnati", "state"=>"Ohio", "country"=>"", "capacity"=>0}], "links"=>{"api"=>{"teams"=>{"href"=>"http://api.espn.com/v1/sports/baseball/mlb/teams/17"}, "news"=>{"href"=>"http://api.espn.com/v1/sports/baseball/mlb/teams/17/news"}, "notes"=>{"href"=>"http://api.espn.com/v1/sports/baseball/mlb/teams/17/news/notes"}}, "web"=>{"teams"=>{"href"=>"http://espn.go.com/mlb/team/_/name/cin/cincinnati-reds?ex_cid=espnapi_public"}}, "mobile"=>{"teams"=>{"href"=>"http://m.espn.go.com/mlb/clubhouse?teamId=17&ex_cid=espnapi_public"}}}}]}]}]
But nothing else parses. Please help!
Like I said, I'm not trying to do anything fancy, just figure out Ruby a little for fun, but I have been stuck on this issue for days now. Any help would be appreciated!
EDIT:
JSON straight from the API:
{"sports" :[{"name" :"baseball","id" :1,"uid" :"s:1","leagues" :[{"name" :"Major League Baseball","abbreviation" :"mlb","id" :10,"uid" :"s:1~l:10","groupId" :9,"shortName" :"MLB","teams" :[{"id" :17,"uid" :"s:1~l:10~t:17","location" :"Cincinnati","name" :"Reds","abbreviation" :"CIN","color" :"D60042","venues" :[{"id" :83,"name" :"Great American Ball Park","city" :"Cincinnati","state" :"Ohio","country" :"","capacity" :0}],"links" :{"api" :{"teams" :{"href" :"http://api.espn.com/v1/sports/baseball/mlb/teams/17"},"news" :{"href" :"http://api.espn.com/v1/sports/baseball/mlb/teams/17/news"},"notes" :{"href" :"http://api.espn.com/v1/sports/baseball/mlb/teams/17/news/notes"}},"web" :{"teams" :{"href" :"http://espn.go.com/mlb/team/_/name/cin/cincinnati-reds?ex_cid=espnapi_public"}},"mobile" :{"teams" :{"href" :"http://m.espn.go.com/mlb/clubhouse?teamId=17&ex_cid=espnapi_public"}}}}]}]}],"resultsOffset" :0,"resultsLimit" :50,"resultsCount" :1,"timestamp" :"2013-08-05T19:44:32Z","status" :"success"}
The result of data.inspect:
"{\"sports\" :[{\"name\" :\"baseball\",\"id\" :1,\"uid\" :\"s:1\",\"leagues\" :[{\"name\" :\"Major League Baseball\",\"abbreviation\" :\"mlb\",\"id\" :10,\"uid\" :\"s:1~l:10\",\"groupId\" :9,\"shortName\" :\"MLB\",\"teams\" :[{\"id\" :17,\"uid\" :\"s:1~l:10~t:17\",\"location\" :\"Cincinnati\",\"name\" :\"Reds\",\"abbreviation\" :\"CIN\",\"color\" :\"D60042\",\"venues\" :[{\"id\" :83,\"name\" :\"Great American Ball Park\",\"city\" :\"Cincinnati\",\"state\" :\"Ohio\",\"country\" :\"\",\"capacity\" :0}],\"links\" :{\"api\" :{\"teams\" :{\"href\" :\"http://api.espn.com/v1/sports/baseball/mlb/teams/17\"},\"news\" :{\"href\" :\"http://api.espn.com/v1/sports/baseball/mlb/teams/17/news\"},\"notes\" :{\"href\" :\"http://api.espn.com/v1/sports/baseball/mlb/teams/17/news/notes\"}},\"web\" :{\"teams\" :{\"href\" :\"http://espn.go.com/mlb/team/_/name/cin/cincinnati-reds?ex_cid=espnapi_public\"}},\"mobile\" :{\"teams\" :{\"href\" :\"http://m.espn.go.com/mlb/clubhouse?teamId=17&ex_cid=espnapi_public\"}}}}]}]}],\"resultsOffset\" :0,\"resultsLimit\" :50,\"resultsCount\" :1,\"timestamp\" :\"2013-08-05T19:44:24Z\",\"status\" :\"success\"}"
parsed["sports"] does not exist, parse your input and inspect it/ dump it
With the data you've provided in the question, you can get to the venues information like this:
require 'json'
json = JSON.parse data
json["sports"].first["leagues"].first["teams"].first["venues"]
# => [{"id"=>83, "name"=>"Great American Ball Park", "city"=>"Cincinnati", "state"=>"Ohio", "country"=>"", "capacity"=>0}]
By replacing each of the first calls with an iterator, you can search through without knowing where the data is:
json["sports"].each{|h|
h["leagues"].each{|h|
h["teams"].each{|h|
venues = h["venues"].map{|h| h["name"]}.join(", ")
puts %Q!name: #{h["location"]} #{h["name"]} venues: #{venues}!
}
}
}
This outputs:
name: Cincinnati Reds venues: Great American Ball Park
Depending on how stable the response data is you may be able to cut out several of the iterators:
json["sports"].first["leagues"]
.first["teams"]
.each{|h|
venues = h["venues"].map{|h| h["name"] }.join(", ")
puts %Q!name: #{h["location"]} #{h["name"]} venues: #{venues}!
}
and you'll most likely want to save the data, so something like each_with_object is helpful:
team_and_venues = json["sports"].first["leagues"]
.first["teams"]
.each_with_object([]){|h,xs|
venues = h["venues"].map{|h| h["name"]}.join(", ")
xs << %Q!name: #{h["location"]} #{h["name"]} venues: #{venues}!
}
# => ["name: Cincinnati Reds venues: Great American Ball Park"]
team_and_venues
# => ["name: Cincinnati Reds venues: Great American Ball Park"]
Notice that when an iterator declares variables, even if there is a variable with the same name outside the block, the scope of the block is respected and the block's variables remain local.
That's some pretty ugly code if you ask me, but it's a place to start.
I'm working with the Koala gem and the Facebook Graph API, and I want to break down the results I get for a users feed into separate variables for inserting into a mySQL database, probably using Active Record. Here is the code I have so far:
#token = Service.where(:provider => 'facebook', :user_id => session[:user_id]).first.token
#graph = Koala::Facebook::GraphAPI.new(#token)
#feeds = params[:page] ? #graph.get_page(params[:page]) : #graph.get_connections("me", "home")
And here is what #feeds looks like:
[{"id"=>"1519989351_1799856285747", "from"=>{"name"=>"April Daggett Swayne", "id"=>"1519989351"},
"picture"=>"http://photos-d.ak.fbcdn.net/hphotos-ak-ash4/270060_1799856805760_1519989351_31482916_3866652_s.jpg",
"link"=>"http://www.facebook.com/photo.php?fbid=1799856805760&set=a.1493877356465.2064294.1519989351&type=1", "name"=>"Mobile Uploads",
"icon"=>"http://static.ak.fbcdn.net/rsrc.php/v1/yx/r/og8V99JVf8G.gif", "type"=>"photo", "object_id"=>"1799856805760", "application"=>{"name"=>"Facebook for Android",
"id"=>"350685531728"}, "created_time"=>"2011-07-03T03:14:04+0000", "updated_time"=>"2011-07-03T03:14:04+0000"}, {"id"=>"2733058_10100271380562998", "from"=>{"name"=>"Joshua Ramirez",
"id"=>"2733058"}, "message"=>"Just posted a photo",
"picture"=>"http://platform.ak.fbcdn.net/www/app_full_proxy.php?app=124024574287414&v=1&size=z&cksum=228788edbab39cb34861aecd197ff458&src=http%3A%2F%2Fimages.instagram.com%2Fmedia%2F2011%2F07%2F02%2F2ad9768378cf405fad404b63bf5e2053_7.jpg",
"link"=>"http://instagr.am/p/G1tp8/", "name"=>"jtrainexpress's photo", "caption"=>"instagr.am",
"icon"=>"http://photos-e.ak.fbcdn.net/photos-ak-snc1/v27562/10/124024574287414/app_2_124024574287414_6936.gif", "actions"=>[{"name"=>"Comment",
"link"=>"http://www.facebook.com/2733058/posts/10100271380562998"}, {"name"=>"Like", "link"=>"http://www.facebook.com/2733058/posts/10100271380562998"}], "type"=>"link",
"application"=>{"name"=>"Instagram", "id"=>"124024574287414"}, "created_time"=>"2011-07-03T02:07:37+0000", "updated_time"=>"2011-07-03T02:07:37+0000"},
{"id"=>"588368718_10150230423643719", "from"=>{"name"=>"Eric Bailey", "id"=>"588368718"}, "link"=>"http://www.facebook.com/pages/Martis-Camp/105474549513998", "name"=>"Martis Camp",
"caption"=>"Eric checked in at Martis Camp.", "description"=>"Rockin the pool", "icon"=>"http://www.facebook.com/images/icons/place.png", "actions"=>[{"name"=>"Comment",
"link"=>"http://www.facebook.com/588368718/posts/10150230423643719"}, {"name"=>"Like", "link"=>"http://www.facebook.com/588368718/posts/10150230423643719"}],
"place"=>{"id"=>"105474549513998", "name"=>"Martis Camp", "location"=>{"city"=>"Truckee", "state"=>"CA", "country"=>"United States", "latitude"=>39.282813917575,
"longitude"=>-120.16736760768}}, "type"=>"checkin", "application"=>{"name"=>"Facebook for iPhone", "id"=>"6628568379"}, "created_time"=>"2011-07-03T01:58:32+0000",
"updated_time"=>"2011-07-03T01:58:32+0000", "likes"=>{"data"=>[{"name"=>"Mike Janes", "id"=>"725535294"}], "count"=>1}}]
I have looked around for clues on this, and haven't found it yet (but I'm still working on my stackoverflow-foo). Any help would be greatly appreciated.
That isn't a Ruby Hash, that's a fragment of a JSON string. First you need to decode into a Ruby data structure:
# If your JSON string is in json...
h = ActiveSupport::JSON.decode(json) # Or your favorite JSON decoder.
Now you'll have a Hash in h so you can access it like any other Hash:
array = h['data']
puts array[0]['id']
# prints out 1111111111_0000000000000
puts array[0]['from']['name']
# prints Jane Done