I've tried adding hashes through #Hash.new with no success, now I am trying .merge as per the forums with limited success as well. I'm trying to add #rand(1..100) into [0] without going into the hash manually. Any ideas?
#age = Hash.new
#email = Hash.new
#age2 = rand(1..100)
people = [
{
"first_name" => "Bob",
"last_name" => "Jones",
"hobbies" => ["basketball", "chess", "phone tag"]
},
{
"first_name" => "Molly",
"last_name" => "Barker",
"hobbies" => ["programming", "reading", "jogging"]
},
{
"first_name" => "Kelly",
"last_name" => "Miller",
"hobbies" => ["cricket", "baking", "stamp collecting"]
}
]
people[0].each do |w|
people.merge({:age => rand(1..100)})
puts "array 0 is #{w}"
end
puts p people
Assuming that's your structure, you do this:
people.each do |person|
person['age'] = rand(1..100)
end
You ideally want to use symbol-style keys instead. That would mean declaring them like this:
people = [
{
first_name: "Bob",
last_name: "Jones",
...
},
...
]
That way you access them like people[0][:first_name]. Your merged in hash uses symbol keys for :age. Remember in Ruby strings and symbols are not equivalent, that is 'bob' != :bob. You should use symbols for regular structures like this, strings for more arbitrary data.
Related
I am new here and i hope that I'm doing everything right.
I also searched the Forum and with Googel, but I didn't find the answer. (Or I did not notice that the solution lies before my eyes. Then I'm sorry >.< .)
i have a problem and i dont exactly know what i am doing wrong at the moment.
I make a API request and get a big JSON back. It looks somehow like that:
"apps": [
{
"title": "XX",
... many more data
},
{
"title": "XX",
... many more data
},
{
"title": "XX",
... many more data
}
... and so on
]
After that i want to create a hash with the data i need, for example it should look like:
{
"APP_0" => {"Title"=>"Name1", "ID"=>"1234", "OS"=>"os"}
"APP_1" => {"Title"=>"Name2", "ID"=>"5678", "OS"=>"os"}
}
but the values in the hash that i create with my code looks like:
"APP_1", {"Title"=>"Name2", "ID"=>"5678", "OS"=>"os"}
dont now if this is a valid hash? And after that i want to iterate through the Hash and just output the ID. But I get an error (TypeError). What am i doing wrong?
require 'json'
require 'net/http'
require 'uri'
require 'httparty'
response = HTTParty.get('https://xxx/api/2/app', {
headers: {"X-Toke" => "xyz"},
})
all_apps_parse = JSON.parse(response.body)
all_apps = Hash.new
all_apps_parse["apps"].each_with_index do |app, i|
all_apps["APP_#{i}"] = {'Title' => app["title"],
'ID' => app["id"],
'OS' => app["platform"]}
end
all_apps.each_with_index do |app, i|
app_id = app["App_#{i}"]["id"]
p app_id
end
I hope someone can understand the problem and can help me :-). Thanks in advance.
Assuming the data looks something like this:
all_apps_parse = { "apps" => [
{
"title" => "Name1",
"id" => 1234,
"platform" => "os"
},
{
"title" => "Name2",
"id" => 5678,
"platform" => "os"
},
{
"title" => "Name3",
"id" => 1111,
"platform" => "windows"
}]
}
and with a little idea of what you want to achieve, here is my solution:
all_apps = Hash.new
all_apps_parse["apps"].each_with_index do |app, i|
all_apps["APP_#{i}"] = { 'Title' => app["title"],
'ID' => app["id"],
'OS' => app["platform"] }
end
all_apps
=> {"APP_0"=>{"Title"=>"Name1", "ID"=>1234, "OS"=>"os"}, "APP_1"=>{"Title"=>"Name2", "ID"=>5678, "OS"=>"os"}, "APP_2"=>{"Title"=>"Name3", "ID"=>1111, "OS"=>"windows"}}
all_apps.each do |key, value|
puts key # => e.g. "APP_0"
puts value['ID'] # => e.g. 1234
end
# Prints
APP_0
1234
APP_1
5678
APP_2
1111
A GET to an API endpoint I'm working with returns json with an inconsistent order of contacts, either
{"contacts"=>[
{"id"=>$UUID_0, "name"=>nil, "email"=>$EMAIL_0, "phone"=>$PHONE_0, "type"=>"foo"},
{"id"=>$UUID_1, "name"=>nil, "email"=>$EMAIL_1, "phone"=>$PHONE_1, "type"=>"bar"}
]}
or
{"contacts"=>[
{"id"=>$UUID_1, "name"=>nil, "email"=>$EMAIL_1, "phone"=>$PHONE_1, "type"=>"bar"},
{"id"=>$UUID_0, "name"=>nil, "email"=>$EMAIL_0, "phone"=>$PHONE_0, "type"=>"foo"}
]}
The "type" values are the only static objects in these responses, so I'd like to map this so that the contact types are keys containing the other pairs:
{
"foo"=>{"id"=>$UUID_0, "name"=>$NAME_0, "email"=>$EMAIL_0, "phone"=>$PHONE_0},
"bar"=>{"id"=>$UUID_1, "name"=>$NAME_1, "email"=>$EMAIL_1, "phone"=>$PHONE_1}
}
A solution is not obvious to me.
If you use Ruby on Rails, or at least ActiveSupport, you can try index_by instead of group_by: it won't put the values into arrays.
hash['contacts'].index_by {|r| r['type']}
=>
{
"bar" => {
"id" => "asdf",
"name" => nil,
"email" => "EMAIL_1",
"phone" => "PHONE_1",
"type" => "bar"
},
"foo" => {
"id" => "asdf",
"name" => nil,
"email" => "EMAIL_0",
"phone" => "PHONE_0",
"type" => "foo"
}
}
Hash[data['contacts'].map { |c| [c['type'], c] }]
This can be done with Enumerable#reduce:
hash['contacts'].reduce({}) {|m,c| m[c['type']] = c;m}
How it works:
An empty hash is the starting point.
The block is called once for each element in the contacts list. The block receives the hash that we're building as m and the current contact as c.
In the block, assign c to the hash based on its type and return the hash so far.
Final result is the last return value of the block.
I have a collection in which one of the field is "type". I want to get some values of each type depending upon condition which is same for all the types. Like I want 2 documents for type A, 2 for type B like that.
How to do this in a single query? I am using Ruby Active Record.
Generally what you are describing is a relatively common question around the MongoDB community which we could describe as the "top n results problem". This is when given some input that is likely sorted in some way, how to get the top n results without relying on arbitrary index values in the data.
MongoDB has the $first operator which is available to the aggregation framework which deals with the "top 1" part of the problem, as this actually takes the "first" item found on a grouping boundary, such as your "type". But getting more than "one" result of course gets a little more involved. There are some JIRA issues on this about modifying other operators to deal with n results or "restrict" or "slice". Notably SERVER-6074. But the problem can be handled in a few ways.
Popular implementations of the rails Active Record pattern for MongoDB storage are Mongoid and Mongo Mapper, both allow access to the "native" mongodb collection functions via a .collection accessor. This is what you basically need to be able to use native methods such as .aggregate() which supports more functionality than general Active Record aggregation.
Here is an aggregation approach with mongoid, though the general code does not alter once you have access to the native collection object:
require "mongoid"
require "pp";
Mongoid.configure.connect_to("test");
class Item
include Mongoid::Document
store_in collection: "item"
field :type, type: String
field :pos, type: String
end
Item.collection.drop
Item.collection.insert( :type => "A", :pos => "First" )
Item.collection.insert( :type => "A", :pos => "Second" )
Item.collection.insert( :type => "A", :pos => "Third" )
Item.collection.insert( :type => "A", :pos => "Forth" )
Item.collection.insert( :type => "B", :pos => "First" )
Item.collection.insert( :type => "B", :pos => "Second" )
Item.collection.insert( :type => "B", :pos => "Third" )
Item.collection.insert( :type => "B", :pos => "Forth" )
res = Item.collection.aggregate([
{ "$group" => {
"_id" => "$type",
"docs" => {
"$push" => {
"pos" => "$pos", "type" => "$type"
}
},
"one" => {
"$first" => {
"pos" => "$pos", "type" => "$type"
}
}
}},
{ "$unwind" => "$docs" },
{ "$project" => {
"docs" => {
"pos" => "$docs.pos",
"type" => "$docs.type",
"seen" => {
"$eq" => [ "$one", "$docs" ]
},
},
"one" => 1
}},
{ "$match" => {
"docs.seen" => false
}},
{ "$group" => {
"_id" => "$_id",
"one" => { "$first" => "$one" },
"two" => {
"$first" => {
"pos" => "$docs.pos",
"type" => "$docs.type"
}
},
"splitter" => {
"$first" => {
"$literal" => ["one","two"]
}
}
}},
{ "$unwind" => "$splitter" },
{ "$project" => {
"_id" => 0,
"type" => {
"$cond" => [
{ "$eq" => [ "$splitter", "one" ] },
"$one.type",
"$two.type"
]
},
"pos" => {
"$cond" => [
{ "$eq" => [ "$splitter", "one" ] },
"$one.pos",
"$two.pos"
]
}
}}
])
pp res
The naming in the documents is actually not used by the code, and titles in the data shown for "First", "Second" etc, are really just there to illustrate that you are indeed getting the "top 2" documents from the listing as a result.
So the approach here is essentially to create a "stack" of the documents "grouped" by your key, such as "type". The very first thing here is to take the "first" document from that stack using the $first operator.
The subsequent steps match the "seen" elements from the stack and filter them, then you take the "next" document off of the stack again using the $first operator. The final steps in there are really justx to return the documents to the original form as found in the input, which is generally what is expected from such a query.
So the result is of course, just the top 2 documents for each type:
{ "type"=>"A", "pos"=>"First" }
{ "type"=>"A", "pos"=>"Second" }
{ "type"=>"B", "pos"=>"First" }
{ "type"=>"B", "pos"=>"Second" }
There was a longer discussion and version of this as well as other solutions in this recent answer:
Mongodb aggregation $group, restrict length of array
Essentially the same thing despite the title and that case was looking to match up to 10 top entries or greater. There is some pipeline generation code there as well for dealing with larger matches as well as some alternate approaches that may be considered depending on your data.
You will not be able to do this directly with only the type column and the constraint that it must be one query. However there is (as always) a way to accomplish this.
To find documents of different types, you would need to have some type of additional value that, on average distributed the types out according to how you want the data back.
db.users.insert({type: 'A', index: 1})
db.users.insert({type: 'B', index: 2})
db.users.insert({type: 'A', index: 3})
db.users.insert({type: 'B', index: 4})
db.users.insert({type: 'A', index: 5})
db.users.insert({type: 'B', index: 6})
Then when querying for items with db.users.find(index: {$gt: 2, $lt: 7}) you will have the right distribution of items.
Though I'm not sure this was what you were looking for
I have this hash,
[{ "player" => { "name" => "Kelvin" , "id" => 1 } , "player" => { "name" => "David",
"id" => 2 }]
I checked if each event contains the keys [id,name] with the following line in my Rspec,
json_response.map{|player| ["name","id"].all? {|attribute| player["player"].key?
(attribute)}}.should_not include(false)
which works perfectly. How can I simplify this and make it more efficient?
How about :
json_response.each do |event|
event['player'].should have_key('name')
event['player'].should have_key('id')
end
Much clearer IMHO
Edit : if you need to check a lot of columns :
json_response.each do |event|
['name', 'id', 'foo', 'bar', 'baz'].each do |column|
event['player'].should have_key(column)
end
end
According to the documentation you should be able to do this:
json_response.each do |event|
event['player'].should include('name', 'id')
end
After parsing some JSON:
data = JSON.parse(data)['info']
puts data
I get:
[
{
"title"=>"CEO",
"name"=>"George",
"columns"=>[
{
"display_name"=> "Salary",
"value"=>"3.85",
}
, {
"display_name"=> "Bonus",
"value"=>"994.19",
}
, {
"display_name"=> "Increment",
"value"=>"8.15",
}
]
}
]
columns has nested data in itself.
I want to save the data in a database or CSV file.
title, name, value_Salary, value_Bonus, value_increment
But I'm not concerned about getting display_name, so just the values of first of columns, second of columns data, etc.
Ok I tried data.map after converting to hash & hash.flatten could find a way out.. .map{|x| x['columns']}
.map {|s| s["value"]}
tried to get the values atleast separately - but couldnt...
This is a simple problem, and resolves down to a couple nested map blocks.
Here's the data retrieved from JSON, plus an extra row to demonstrate how easy it is to handle a more complex JSON response:
data = [
{
"title" => "CEO",
"name" => "George",
"columns" => [
{
"display_name" => "Salary",
"value" => "3.85",
},
{
"display_name" => "Bonus",
"value" => "994.19",
},
{
"display_name" => "Increment",
"value" => "8.15",
}
]
},
{
"title" => "CIO",
"name" => "Fred",
"columns" => [
{
"display_name" => "Salary",
"value" => "3.84",
},
{
"display_name" => "Bonus",
"value" => "994.20",
},
{
"display_name" => "Increment",
"value" => "8.15",
}
]
}
]
Here's the code:
records = data.map { |record|
title, name = record.values_at('title', 'name')
values = record['columns'].map{ |column| column['value'] }
[title, name, *values]
}
Here's the resulting data structure, an array of arrays:
records
# => [["CEO", "George", "3.85", "994.19", "8.15"],
# ["CIO", "Fred", "3.84", "994.20", "8.15"]]
Saving it into a database or CSV is left for you to figure out, but Ruby's CSV class makes it trivial to write a file, and an ORM like Sequel makes it really easy to insert the data into a database.