I am trying this for the first time and am not sure I have quite achieved what i want to. I am pulling in data via a screen scrape as arrays and want to put them into a hash.
I have a model with columns :home_team and :away_team and would like to post the data captured via the screen scrape to these
I was hoping someone could quickly run this in a rb file
require 'open-uri'
require 'nokogiri'
FIXTURE_URL = "http://www.bbc.co.uk/sport/football/premier-league/fixtures"
doc = Nokogiri::HTML(open(FIXTURE_URL))
home_team = doc.css(".team-home.teams").map {|team| team.text.strip}
away_team = doc.css(".team-away.teams").map {|team| team.text.strip}
team_clean = Hash[:home_team => home_team, :away_team => away_team]
puts team_clean.inspect
and advise if this is actually a hash as it seems to be an array as i cant see the hash name being outputted. i would of expected something like this
{"team_clean"=>[{:home_team => "Man Utd", "Chelsea", "Liverpool"},
{:away_team => "Swansea", "Cardiff"}]}
any help appreciated
You actually get a Hash back. But it looks different from the one you expected. You expect a Hash inside a Hash.
Some examples to clarify:
hash = {}
hash.class
=> Hash
hash = { home_team: [], away_team: [] }
hash.class
=> Hash
hash[:home_team].class
=> Array
hash = { hash: { home_team: [], away_team: [] } }
hash.class
=> Hash
hash[:hash].class
=> Hash
hash[:hash][:home_team].class
=> Array
The "Hash name" as you call it, is never "outputed". A Hash is basically a Array with a different index. To clarify this a bit:
hash = { 0 => "A", 1 => "B" }
array = ["A", "B"]
hash[0]
=> "A"
array[0]
=> "A"
hash[1]
=> "B"
array[1]
=> "B"
Basically with a Hash you additionally define, how and where to find the values by defining the key explicitly, while an array always stores it with a numerical index.
here is the solution
team_clean = Hash[:team_clean => [Hash[:home_team => home_team,:away_team => away_team]]]
Related
first_response = [
{"xId" => "123", "yId" => "321"},
{"xId" => "x", "yId" => "y" }
]
first_response.each do |resp|
x_id = resp['xId']
y_id = resp['yId']
puts x_id.to_s
puts y_id.to_s
end
This gives me outputs
123
321
x
y
output hash I want to create is
{123=>{321}, x=>{y}}
first service: I have an array of hash that has two different ids example:(x_id and y_id) (there would be multiple pairs like that in the response)
I want to create a hash that should contain the matching pair of x_id and y_ids that we get from the first service with x_id's as the key for all the pairs.
If you know every hash in first_response is going to contain exactly two key/value pairs, you can extract their values and then convert that result into a hash (see Enumerable#to_h):
first_response.to_h(&:values)
# {"123"=>"321", "x"=>"y"}
Looks like this approach works, but I am not completely sure if that is right
first_response = [{"xId"=>"123","yId"=> "321"}, {"xId"=>"x","yId"=> "y"}]
h = {}.tap do |element|
first_response.each do |resp|
x_id = resp['xId']
y_id = resp['yId']
element[x_id] = y_id
end
end
puts h.to_s
# {"123"=>"321", "x"=>"y"}
I have a hash in rails like so:
{"unique_id" => "1",
"unique_id2" => "2",
"unique_id3" => "n"}
Each unique key has a count that can be a number 1-20. What I would like to do is have a hash that looks like this:
{"1" => ["unique_id", "unique_id2"],
"2" => ["unique_id3"],
"3" => ["unique_id4", "unique_id5", "uniqueid6"]}
How would I go about doing that with a hash?
Not too hard!
hash = { "unique_id" => "1",
"unique_id2" => "2",
"unique_id3" => "n"
}
new_hash = hash.each_with_object({}) { |(k,v), h| (h[v] ||= []) << k }
each_with_object({}) is just an each loop with a blank hash
||= [] means if the hash doesn't have a value for v, set it equal to an empty array
<< k pushes the key onto the array
Try this:
h.group_by{|k,v| v }.each{|k,v| v.map!(&:first) }
group_by takes your hash and groups it by value
each iterates over the result hash
map! maps the first elements of the result value arrays, since group_by on a Hash returns two-dimensional Arrays with the structure [key, value]
I have a Rails nested hash as follow:
class = [{"tutor" => {"id" => "Me"}}, {"tutor" => {}}]
I would like to extract id list, but the nested hash can be nil:
tutor_ids = class.map {|c| c['tutor']['id'].to_i }
In case the nested hash is nil, I'll get error.
How do I go about this?
First of all I think you were probably thinking of an array of hashes like so (given the same key was used multiple times:
klass = [{"tutor" => {"id" => "Me"}},{"tutor" => {}}]
Then you could map the tutor IDs with:
tutor_ids = klass.map {|k| k['tutor'] && k['tutor']['id'] }.compact
which would result in
=> ["Me"]
Compact will throw out all the nil values encountered afterwards.
id = class['tutor'] ? class['tutor']['id'] : nil
I have an array of hashes, this is not an active record model. This array is of objects of type Person with properties of id, name, age. I have a second array of strings, ["john", "james", "bill"].
I am attempting to remove all objects in the array of hashes except for the ones who have names in the second array, essentially performing an intersect, but I'm having quite a few problems. Any suggestions? I'm not sure if my syntax is just off or if I'm thinking about this the wrong way. Obviously I can just iterate through but this seems like its probably not the best way to handle the situation.
http://www.ruby-doc.org/core-1.9.2/Array.html#method-i-select
arr1 = [{:id => 1, :name => "John"}, {:id => 2, :name => "Doe"}];
arr2 = ["Doe"];
intersect = arr1.select {|o| arr2.include? o[:name]} # you can also use select!
p intersect # outputs [{:name=>"Doe", :id=>2}]
Late to the party, but if arr1 :name is an array this works nicely:
arr1 = [{:id => 1, :name => ["John", "Doe"]}, {:id => 2, :name => ["Doe"]}];
arr2 = ["Doe"]
> intersect = arr1.reject{|o| (arr2 & o[:name]).empty?}
=> [{:id=>1, :name=>["John", "Doe"]}, {:id=>2, :name=>["Doe"]}] #output
> arr2 = ["John"]
> intersect = arr1.reject{|o| (arr2 & o[:name]).empty?}
=> [{:id=>1, :name=>["John", "Doe"]}] #output
or use select:
intersect = arr1.select{|o| !(arr2 & o[:name]).empty?}
To remove all objects in the array of hashes except for the ones who have names in the second array, you can do:
arr1.reject!{|o| (arr2 & o[:name]).empty?}
I have an array that contains dates and values. An example of how it might look:
[
{'1/1/2010' => 'aa'},
{'1/1/2010' => 'bb'},
{'1/2/2010' => 'cc'},
{'1/2/2010' => 'dd'},
{'1/3/2010' => 'ee'}
]
Notice that some of the dates repeat. I'm trying to output this in a table format and I only want to show unique dates. So I loop through it with the following code to get my desired output.
prev_date = nil
#reading_schedule.reading_plans.each do |plan|
use_date = nil
if plan.assigned_date != prev_date
use_date = plan.assigned_date
end
prev_date = plan.assigned_date
plan.assigned_date = use_date
end
The resulting table will then look something like this
1/1/2010 aa
bb
1/2/2010 cc
dd
1/3/2010 ee
This work fine but I am new to ruby and was wondering if there was a better way to do this.
Enumerable.group_by is a good starting point:
require 'pp'
asdf = [
{'1/1/2010' => 'aa'},
{'1/1/2010' => 'bb'},
{'1/2/2010' => 'cc'},
{'1/2/2010' => 'dd'},
{'1/3/2010' => 'ee'}
]
pp asdf.group_by { |n| n.keys.first }.map{ |a,b| { a => b.map { |c| c.to_a.last.last } } }
# >> [{"1/1/2010"=>["aa", "bb"]}, {"1/2/2010"=>["cc", "dd"]}, {"1/3/2010"=>["ee"]}]
Which should be a data structure you can bend to your will.
I don't know as though it's better, but you could group the values by date using (e.g.) Enumerable#reduce (requires Ruby >= 1.8.7; before that, you have Enumerable#inject).
arr.reduce({}) { |memo, obj|
obj.each_pair { |key, value|
memo[key] = [] if ! memo.has_key?(key);
memo[key] << value
}
memo
}.sort
=> [["1/1/2010", ["aa", "bb"]], ["1/2/2010", ["cc", "dd"]], ["1/3/2010", ["ee"]]]
You could also use Array#each to similar effect.
This is totally a job for a hash.
Create a hash and use the date as the hashkey and an empty array as the hashvalue.
Then accumulate the values from the original array in the hashvalue array