I have the following string and I would like to convert it to a hash printing the below result
string = "Cow, Bill, Phone, Flour"
hash = string.split(",")
>> {:animal => "Cow", :person: "Bill", :gadget => "Phone",
:grocery => "Flour"}
hash = Hash[[:animal, :person, :gadget, :grocery].zip(string.split(/,\s*/))]
The answer by #Max is quite nice. You might understand it better as:
def string_to_hash(str)
values = str.split(/,\s*/)
names = [:animal, :person, :gadget, :grocery]
Hash[names.zip(values)]
end
Here is a less sophisticated approach:
def string_to_hash(str)
parts = str.split(/,\s*/)
Hash[
:animal => parts[0],
:person => parts[1],
:gadget => parts[2],
:grocery => parts[3],
]
end
Related
I am trying to create a nested hash from an array that has several elements saved to it. I've tried experimenting with each_with_object, each_with_index, each and map.
class Person
attr_reader :name, :city, :state, :zip, :hobby
def initialize(name, hobby, city, state, zip)
#name = name
#hobby = hobby
#city = city
#state = state
#zip = zip
end
end
steve = Person.new("Steve", "basketball","Dallas", "Texas", 75444)
chris = Person.new("Chris", "piano","Phoenix", "Arizona", 75218)
larry = Person.new("Larry", "hunting","Austin", "Texas", 78735)
adam = Person.new("Adam", "swimming","Waco", "Texas", 76715)
people = [steve, chris, larry, adam]
people_array = people.map do |person|
person = person.name, person.hobby, person.city, person.state, person.zip
end
Now I just need to turn it into a hash. One issue I am having is, when I'm experimenting with other methods, I can turn it into a hash, but the array is still inside the hash. The expected output is just a nested hash with no arrays inside of it.
# Expected output ... create the following hash from the peeps array:
#
# people_hash = {
# "Steve" => {
# "hobby" => "golf",
# "address" => {
# "city" => "Dallas",
# "state" => "Texas",
# "zip" => 75444
# }
# # etc, etc
Any hints on making sure the hash is a nested hash with no arrays?
This works:
person_hash = Hash[peeps_array.map do |user|
[user[0], Hash['hobby', user[1], 'address', Hash['city', user[2], 'state', user[3], 'zip', user[4]]]]
end]
Basically just use the ruby Hash [] method to convert each of the sub-arrays into an hash
Why not just pass people?
people.each_with_object({}) do |instance, h|
h[instance.name] = { "hobby" => instance.hobby,
"address" => { "city" => instance.city,
"state" => instance.state,
"zip" => instance.zip } }
end
The objective of the code below is to produce a hash with the keys being the :id field of
the hashes in original_array, and the values being all elements in original_array which have that :id.
original_array = [
{:id => '123', :name => 'test'},
{:id => '123', :name => 'another test'},
{:id => '456', :name => 'yet another test'}
]
new_hash = {}
original_array.each do |a|
new_hash[a[:id]] = original_array.select {|x| x[:id] == a[:id]}
end
My code does that, but there must be some better way to do it, ideally where the hash can be created in one step. If anyone can suggest and explain one (in the hope that I might improve my understanding of this sort of thing), then it would be appreciated.
This should do it
new_hash = original_array.group_by{|h| h[:id]}
Documentation: Enumerable#group_by.
Given I have the following code:
ENDPOINT = 'http://api.eventful.com'
API_KEY = 'PbFVZfjTXJQWrnJp'
def get_xml(url, options={})
compiled_url = "#{ENDPOINT}/rest#{url}" << "?app_key=#{API_KEY}&sort_order=popularity"
options.each { |k, v| compiled_url << "&#{k.to_s}=#{v.to_s}" }
REXML::Document.new((Net::HTTP.get(URI.parse(URI.escape(compiled_url)))))
end
def event_search(location, date)
get_xml('/events/search',
:location => "#{location}, United Kingdom",
:date => date
)
end
And we access the XML data formatted by REXML::Document like this:
events = event_search('London', 'Today').elements
And we can access these elements like this (this prints all the titles in the events):
events.each('search/events/event/title') do |title|
puts title.text
end
The XML I'm using can be found here. I would like this construct a Hash like so:
{"Title1" => {:title => 'Title1', :date => 'Date1', :post_code => 'PostCode1'},
"Title2" => {:title => 'Title2', :date => 'Date2', :post_code => 'PostCode2'}}
When using events.each('search/events/event/title'), events.each('search/events/event/date'), and events.each('search/events/event/post_code').
So I want to create a Hash from the XML provided by the URL I have included above. Thanks!
You should loop over the events themselves, not the titles. Something like this
events_by_title = {}
elements.each('search/events/event') do |event|
title = event.get_elements('title').first.text
events_by_title[title] = {
:title => title,
:date => event.get_elements('start_time').first.text
:post_code => event.get_elements('postal_code').first.text,
}
end
Get the root element using root() on the REXML:Document object then use each_element("search/events/event") to iterate over "event" node. You can then extract the different values out of it using the different methods on element: http://ruby-doc.org/stdlib-1.9.3/libdoc/rexml/rdoc/REXML/Element.html
Let's say I have the following array of hashes:
h = [{"name" => "bob"}, {"car" => "toyota"}, {"age" => "25"}]
And I have the following key to match:
k = 'car'
How do I match the 'k' to 'h' and have delete every element after the match so that it returns:
h = [{"name" => "bob"}, {"car" => "toyota"}]
Just convert hash to array, do your task and then convert back
h = {"name" => "bob", "car" => "toyota", "age" => "25"}
array = h.to_a.flatten
index = array.index('car') + 1
h = Hash[*array[0..index]]
=> {"name"=>"bob", "car"=>"toyota"}
By the way, the hash is ordered only since Ruby 1.9
ar = [{"name" => "bob"}, {"car" => "toyota"}, {"age" => "25"}]
p ar[0 .. ar.index{|h| h.key?('car')}] #=>[{"name"=>"bob"}, {"car"=>"toyota"}]
I like megas' version, as its short and to the point. Another approach, which would be more explicit, would be iterating over the keys array of each hash. The keys of a hash are maintained in an ordered array (http://ruby-doc.org/core-1.9.3/Hash.html). They are ordered by when they were first entered. As a result, you can try the following:
newArray = Array.new
h.each do |hash| # Iterate through your array of hashes
newArray << hash
if hash.has_key?("car") # check if this hash is the "car" hash.
break # exits the block
end
end
This all depends, of course, on whether the array was created in the proper order. If it was, then you're golden.
A hash is unordered set by definition, so what you request is somewhat undefined. However you can do something like a hack:
h = {"name" => "bob", "car" => "toyota", "age" => "25"}
matched = false
key_given = "car"
h.each do |k,v|
if matched
h.delete(k)
end
if k == key_given
matched = true
next
end
end
I'm pretty late to the party here. I was looking for a solution to this same problem, but I didn't love these answers. So, here's my approach:
class Array
def take_until(&blk)
i = find_index &blk
take(i + 1)
end
end
h = [{"name" => "bob"}, {"car" => "toyota"}, {"age" => "25"}]
k = 'car'
h.take_until { |x| x.has_key?(k) }
=> [{"name"=>"bob"}, {"car"=>"toyota"}]
I have hash (#post) of hashes where I want to keep the order of the hash's keys in the array (#post_csv_order) and also want to keep the relationship key => value in the array.
I don't know the final number of both #post hashes and key => value elements in the array.
I don't know how to assign the hash in a loop for all elements in the array. One by one #post_csv_order[0][0] => #post_csv_order[0][1] works nicely.
# require 'rubygems'
require 'pp'
#post = {}
forum_id = 123 #only sample values.... to make this sample script work
post_title = "Test post"
#post_csv_order = [
["ForumID" , forum_id],
["Post title", post_title]
]
if #post[forum_id] == nil
#post[forum_id] = {
#post_csv_order[0][0] => #post_csv_order[0][1],
#post_csv_order[1][0] => #post_csv_order[1][1]
##post_csv_order.map {|element| element[0] => element[1]}
##post_csv_order.each_index {|index| #post_csv_order[index][0] => #post_csv_order[index][1] }
}
end
pp #post
desired hash assignment should be like that
{123=>{"Post title"=>"Test post", "ForumID"=>123}}
The best way is to use to_h:
[ [:foo,1],[:bar,2],[:baz,3] ].to_h #=> {:foo => 1, :bar => 2, :baz => 3}
Note: This was introduced in Ruby 2.1.0. For older Ruby, you can use my backports gem and require 'backports/2.1.0/array/to_h', or else use Hash[]:
array = [[:foo,1],[:bar,2],[:baz,3]]
# then
Hash[ array ] #= > {:foo => 1, :bar => 2, :baz => 3}
This is available in Ruby 1.8.7 and later. If you are still using Ruby 1.8.6 you could require "backports/1.8.7/hash/constructor", but you might as well use the to_h backport.
I am not sure I fully understand your question but I guess you want to convert a 2d array in a hash.
So suppose you have an array such as:
array = [[:foo,1],[:bar,2],[:baz,3]]
You can build an hash with:
hash = array.inject({}) {|h,e| h[e[0]] = e[1]; h}
# => {:foo=>1, :bar=>2, :baz=>3}
And you can retrieve the keys in correct order with:
keys = array.inject([]) {|a,e| a << e[0] }
=> [:foo, :bar, :baz]
Is it what you were looking for ?
Answers summary
working code #1
#post[forum_id] = #post_csv_order.inject({}) {|h,e| h[e[0]] = e[1]; h}
working code #2
#post[forum_id] = Hash[*#post_csv_order.flatten]
working code #3
#post[forum_id] ||= Hash[ #post_csv_order ] #requires 'require "backports"'