Active Support's deep_transform_values recursively transforms all values of a hash. However, is there a similar method that would allow to access the keys of values while transforming?
I'd like to be able to do the following:
keys_not_to_transform = ['id', 'count']
response = { result: 'ok', errors: [], data: { id: '123', price: '100.0', quotes: ['1.0', '2.0'] }, count: 10 }
response.deep_transform_values! do |key, value|
# Use value's key to help decide what to do
return value if keys_not_to_transform.any? key.to_s
s = value.to_s
if s.present? && /\A[+-]?\d+(\.\d+)?\z/.match?(s)
return BigDecimal(s)
else
value
end
end
#Expected result
# =>{:result=>"ok", :errors=>[], :data=>{:id=>"123", :price=>0.1e3, :quotes=>[0.1e1, 0.2e1]}, :count=>10}
Note that we are not interested in transforming the key itself, just having it on hand while transforming the corresponding values.
You could use Hash#deep_merge! (provided by ActiveSupport) like so:
keys_not_to_transform = ['id', 'count']
transform_value = lambda do |value|
s = value.to_s
if s.present? && /\A[+-]?\d+(\.\d+)?\z/.match?(s)
BigDecimal(s)
else
value
end
end
transform = Proc.new do |key,value|
if keys_not_to_transform.include? key.to_s
value
elsif value.is_a?(Array)
value.map! do |v|
v.is_a?(Hash) ? v.deep_merge!(v,&transform) : transform_value.(v)
end
else
transform_value.(value)
end
end
response = { result: 'ok', errors: [], data: { id: '123', price: '100.0', quotes: ['1.0', '2.0'], other: [{id: '124', price: '17.0'}] }, count: 10 }
response.deep_merge!(response, &transform)
This outputs:
#=>{:result=>"ok", :errors=>[], :data=>{:id=>"123", :price=>0.1e3, :quotes=>[0.1e1, 0.2e1], :other=>[{:id=>"124", :price=>0.17e2}]}, :count=>10}
I'd just implement the necessary transformation logic with plain old Ruby and a bit of recursion, no external dependencies needed. For example:
def transform(hash, ignore_keys: [])
hash.each_with_object({}) do |(key, value), result|
if value.is_a?(Hash)
result[key] = transform(value, ignore_keys: ignore_keys)
elsif ignore_keys.include?(key.to_s)
result[key] = value
elsif value.to_s =~ /\A[+-]?\d+(\.\d+)?\z/
result[key] = BigDecimal(value)
else
result[key] = value
end
end
end
keys_not_to_transform = %w[id count]
response = { result: 'ok', errors: [], data: { id: '123', price: '100.0' }, count: 10 }
transform(response, ignore_keys: keys_not_to_transform)
# => {:result=>"ok", :errors=>[], :data=>{:id=>"123", :price=>#<BigDecimal:5566613bb128,'0.1E3',9(18)>}, :count=>10}
Related
I am trying to parse a string into a hash.
str = "Notifications[0].Open=1
Notifications[0].Body.Message[0]=3455
Notifications[0].Body.Message[1]=2524
Notifications[0].Body.Message[2]=2544
Notifications[0].Body.Message[3]=2452
Notifications[0].Body.Error[0]=2455
Notifications[0].Body.Currency=EUR
Notifications[0].Published=true"
The result should look similar to this:
pairs = {
'Open' = 1,
'Published' => true
'Body' => {
'Message' => [3455, 2524, 2544, 2452],
'Error' => [2455],
'Currency' => 'EUR',
}
}
Maybe someone can help on how I can make it. The only way I can think as for now is regexp.
something like this with regexp:
require 'pp'
str = "Notifications[0].Open=1
Notifications[0].Body.Message[0]=3455
Notifications[0].Body.Message[1]=2524
Notifications[0].Body.Message[2]=2544
Notifications[0].Body.Message[3]=2452
Notifications[0].Body.Error[0]=2455
Notifications[0].Body.Currency=EUR
Notifications[0].Published=true"
pairs = {}
pairs['Body'] = {}
values = []
str.scan(/Body\W+(.+)/).flatten.each do |line|
key = line[/\A\w+/]
value = line[/\w+\z/]
if line[/\A\w+\[\d+\]/] || key == 'Error'
values = [] unless pairs['Body'][key]
values << value
value = values
end
pairs['Body'][key] = value
end
str.scan(/\[0\]\.(?!Body.).*/).each do |line|
key = line[/(?!\A)\.(\w+)/, 1]
value = line[/\w+\z/]
if line[/\A\w+\[\d+\]/]
values = [] unless pairs[key]
values << value
value = values
end
pairs[key] = value
end
PP.pp pairs
-
{"Body"=>
{"Message"=>["3455", "2524", "2544", "2452"],
"Error"=>["2455"],
"Currency"=>"EUR"},
"Open"=>"1",
"Published"=>"true"}
Here it is. This code should work with any structure.
def parse(path, value, hash)
key, rest = path.split('.', 2)
if rest.nil?
hash[key] = value
else
hash[key] ||= {}
parse(rest, value, hash[key])
end
end
def conv_to_array(hash)
if hash.is_a?(Hash)
hash.each do |key, value|
hash[key] = if value.is_a?(Hash) && value.keys.all? { |k| k !~ /\D/ }
arr = []
value.each do |k, v|
arr[k.to_i] = conv_to_array(v)
end
arr
else
conv_to_array(value)
end
end
hash
else
if hash !~ /\D/
hash.to_i
elsif hash == 'true'
true
elsif hash == 'false'
false
else
hash
end
end
end
str = "Notifications[0].Open=1
Notifications[0].Body.Message[0]=3455
Notifications[0].Body.Message[1]=2524
Notifications[0].Body.Message[2]=2544
Notifications[0].Body.Message[3]=2452
Notifications[0].Body.Error[0]=2455
Notifications[0].Body.Currency=EUR
Notifications[0].Published=true"
str = str.tr('[', '.').tr(']', '')
hash = {}
str.split(' ').each do |chunk|
path, value = chunk.split('=')
parse(path.strip, value.strip, hash)
end
hash = conv_to_array(hash)
hash['Notifications'][0]
# => {"Open"=>1, "Body"=>{"Message"=>[3455, 2524, 2544, 2452], "Error"=>[2455], "Currency"=>"EUR"}, "Published"=>true}
I am trying to create a function that outputs the key and value for all entries of that JSON as described below so I can use it to send information similar to this:
key = "id", value = 1
key = "mem/stat1", value = 10
key = "more_stats/extra_stats/stat7", value = 5
Example JSON :
my_json =
{
"id": 1,
"system_name": "System_1",
"mem" : {
"stat1" : 10,
"stat2" : 1056,
"stat3" : 10563,
},
"other_stats" : {
"stat4" : 1,
"stat5" : 2,
"stat6" : 3,
},
"more_stats" : {
"name" : "jdlfjsdlfjs",
"os" : "fjsalfjsl",
"error_count": 3
"extra_stats" : {
"stat7" : 5,
"stat8" : 6,
},
}
}
I found an answer from this question (need help in getting nested ruby hash hierarchy) that was helpful but even with some alterations it isn't working how I would like it:
def hashkeys(json, keys = [], result = [])
if json.is_a?(Hash)
json.each do |key, value|
hashkeys(value, keys + [key], result)
end
else
result << keys
end
result.join("/")
end
It returns all the keys together as one string and doesn't include any of the respective values correctly as I would like.
Unwanted output of hashkeys currently:
id/system_name/mem/stat1/mem/stat2/...
Ideally I want something that takes in my_json:
find_nested_key_value(my_json)
some logic loop involving key and value:
if more logic needed
another_logic_loop_for_more_nested_info
else
send_info(final_key, final_value)
end
end
end
So if final_key = "mem/stat1" then the final_value = 10, then the next iteration would be final_key = "mem/stat2" and final_value = 1056 and so on
How do I achieve this? and is using a function like hashkeys the best way to achieve this
This is a recursive method that will create a "flattened hash", a hash without nesting and where the keys are the nested keys separated by slashes.
def flatten_hash(hash, result = {}, prefix = nil)
hash.each do |k,v|
if v.is_a? Hash
flatten_hash(v, result, [prefix, k].compact.join('/'))
else
result[[prefix, k].compact.join('/')] = v
end
end
result
end
my_hash = {'id': 1, 'system_name': 'Sysem_1', 'mem': {'stat1': 10, 'stat2': 1056, 'stat3': 10563}}
flatten_hash(my_hash)
=> {"id"=>1, "system_name"=>"Sysem_1", "mem/stat1"=>10, "mem/stat2"=>1056, "mem/stat3"=>10563}
def key_path_value(key_string, my_json)
value = nil
key_array = key_string.split("/")
return value if key_array.empty?
return my_json[key_array.last] if key_array.length == 1
value = my_json[key_array.first.to_sym]
key_array = key_array.drop(1)
key_array.each do |key|
break unless value.is_a? Hash
value = value[key.to_sym]
end
return value
end
Lets say I have something like this:
class FruitCount
attr_accessor :name, :count
def initialize(name, count)
#name = name
#count = count
end
end
obj1 = FruitCount.new('Apple', 32)
obj2 = FruitCount.new('Orange', 5)
obj3 = FruitCount.new('Orange', 3)
obj4 = FruitCount.new('Kiwi', 15)
obj5 = FruitCount.new('Kiwi', 1)
fruit_counts = [obj1, obj2, obj3, obj4, obj5]
Now what I need, is a function build_fruit_summary which due to a given fruit_counts array, it returns the following summary:
fruits_summary = {
fruits: [
{
name: 'Apple',
count: 32
},
{
name: 'Orange',
count: 8
},
{
name: 'Kiwi',
count: 16
}
],
total: {
name: 'AllFruits',
count: 56
}
}
I just cannot figure out the best way to do the aggregations.
Edit:
In my example I have more than one count.
class FruitCount
attr_accessor :name, :count1, :count2
def initialize(name, count1, count2)
#name = name
#count1 = count1
#count2 = count2
end
end
Ruby's Enumerable is your friend, particularly each_with_object which is a form of reduce.
You first need the fruits value:
fruits = fruit_counts.each_with_object([]) do |fruit, list|
aggregate = list.detect { |f| f[:name] == fruit.name }
if aggregate.nil?
aggregate = { name: fruit.name, count: 0 }
list << aggregate
end
aggregate[:count] += fruit.count
aggregate[:count2] += fruit.count2
end
UPDATE: added multiple counts within the single fruity loop.
The above will serialize each fruit object - maintaining a count for each fruit - into a hash and aggregate them into an empty list array, and assign the aggregate array to the fruits variable.
Now, get the total value:
total = { name: 'AllFruits', count: fruit_counts.map { |f| f.count + f.count2 }.reduce(:+) }
UPDATE: total taking into account multiple count attributes within a single loop.
The above maps the fruit_counts array, plucking each object's count attribute, resulting in an array of integers. Then, reduce is getting the sum of the array's integers.
Now put it all together into the summary:
fruits_summary = { fruits: fruits, total: total }
You can formalize this in an OOP style by introducing a FruitCollection object that uses the Enumerable module:
class FruitCollection
include Enumerable
def initialize(fruits)
#fruits = fruits
end
def summary
{ fruits: fruit_counts, total: total }
end
def each(&block)
#fruits.each &block
end
def fruit_counts
each_with_object([]) do |fruit, list|
aggregate = list.detect { |f| f[:name] == fruit.name }
if aggregate.nil?
aggregate = { name: fruit.name, count: 0 }
list << aggregate
end
aggregate[:count] += fruit.count
aggregate[:count2] += fruit.count2
end
end
def total
{ name: 'AllFruits', count: map { |f| f.count + f.count2 }.reduce(:+) }
end
end
Now pass your fruit_count array into that object:
fruit_collection = FruitCollection.new fruit_counts
fruits_summary = fruit_collection.summary
The reason the above works is by overriding the each method which Enumerable uses under the hood for every enumerable method. This means we can call each_with_object, reduce, and map (among others listed in the enumerable docs above) and it will iterate over the fruits since we told it to in the above each method.
Here's an article on Enumerable.
UPDATE: your multiple counts can be easily added by adding a total attribute to your fruit object:
class FruitCount
attr_accessor :name, :count1, :count2
def initialize(name, count1, count2)
#name = name
#count1 = count1
#count2 = count2
end
def total
#count1 + #count2
end
end
Then just use fruit.total whenever you need to aggregate the totals:
fruit_counts.map(&:total).reduce(:+)
fruits_summary = {
fruits: fruit_counts
.group_by { |f| f.name }
.map do |fruit_name, objects|
{
name: fruit_name,
count: objects.map(&:count).reduce(:+)
}
end,
total: {
name: 'AllFruits',
count: fruit_counts.map(&:count).reduce(:+)
}
}
Not very efficient way, though :)
UPD: fixed keys in fruits collection
Or slightly better version:
fruits_summary = {
fuits: fruit_counts
.reduce({}) { |acc, fruit| acc[fruit.name] = acc.fetch(fruit.name, 0) + fruit.count; acc }
.map { |name, count| {name: name, count: count} },
total: {
name: 'AllFruits',
count: fruit_counts.map(&:count).reduce(:+)
}
}
counts = fruit_counts.each_with_object(Hash.new(0)) {|obj, h| h[obj.name] += obj.count}
#=> {"Apple"=>32, "Orange"=>8, "Kiwi"=>16}
fruits_summary =
{ fruits: counts.map { |name, count| { name: name, count: count } },
total: { name: 'AllFruits', count: counts.values.reduce(:+) }
}
#=> {:fruits=>[
# {:name=>"Apple", :count=>32},
# {:name=>"Orange", :count=> 8},
# {:name=>"Kiwi", :count=>16}],
# :total=>
# {:name=>"AllFruits", :count=>56}
# }
I have an array with hashes in it. If they have the same key I just want to add its value.
#receivers << result
#receivers
=> [{:email=>"user_02#yorlook.com", :amount=>10.00}]
result
=> {:email=>"user_02#yorlook.com", :amount=>7.00}
I want the result of above to look like this
[{:email=>"user_02#yorlook.com", :amount=>17.00}]
Does anyone know how to do this?
Here is the the entire method
def receivers
#receivers = []
orders.each do |order|
product_email = order.product.user.paypal_email
outfit_email = order.outfit_user.paypal_email
if order.user_owns_outfit?
result = { email: product_email, amount: amount(order.total_price) }
else
result = { email: product_email, amount: amount(order.total_price, 0.9),
email: outfit_email, amount: amount(order.total_price, 0.1) }
end
#receivers << result
end
end
Using Enumerable#group_by
#receivers.group_by {|h| h[:email]}.map do |k, v|
{email: k, amount: v.inject(0){|s,h| s + h[:amount] } }
end
# => [{:email=>"user_02#yorlook.com", :amount=>17.0}]
Using Enumerable#each_with_object
#receivers.each_with_object(Hash.new(0)) {|h, nh| nh[h[:email]]+= h[:amount] }.map do |k, v|
{email: k, amount: v}
end
# Output: [{ "em#il.one" => 29.0 }, { "em#il.two" => 39.0 }]
def receivers
return #receivers if #receivers
# Produces: { "em#il.one" => 29.0, "em#il.two" => 39.0 }
partial_result = orders.reduce Hash.new(0.00) do |result, order|
product_email = order.product.user.paypal_email
outfit_email = order.outfit_user.paypal_email
if order.user_owns_outfit?
result[product_email] += amount(order.total_price)
else
result[product_email] += amount(order.total_price, .9)
result[outfit_email] += amount(order.total_price, .1)
end
result
end
#receivers = partial_result.reduce [] do |result, (email, amount)|
result << { email => amount }
end
end
I would just write the code this way:
def add(destination, source)
if destination.nil?
return nil
end
if source.class == Hash
source = [source]
end
for item in source
target = destination.find {|d| d[:email] == item[:email]}
if target.nil?
destination << item
else
target[:amount] += item[:amount]
end
end
destination
end
usage:
#receivers = []
add(#receivers, {:email=>"user_02#yorlook.com", :amount=>10.00})
=> [{:email=>"user_02#yorlook.com", :amount=>10.0}]
add(#receivers, #receivers)
=> [{:email=>"user_02#yorlook.com", :amount=>20.0}]
a = [
{:email=>"user_02#yorlook.com", :amount=>10.0},
{:email=>"user_02#yorlook.com", :amount=>7.0}
]
a.group_by { |v| v.delete :email } # group by emails
.map { |k, v| [k, v.inject(0) { |memo, a| memo + a[:amount] } ] } # sum amounts
.map { |e| %i|email amount|.zip e } # zip to keys
.map &:to_h # convert nested arrays to hashes
From what I understand, you could get away with just .inject:
a = [{:email=>"user_02#yorlook.com", :amount=>10.00}]
b = {:email=>"user_02#yorlook.com", :amount=>7.00}
c = {email: 'user_03#yorlook.com', amount: 10}
[a, b, c].flatten.inject({}) do |a, e|
a[e[:email]] ||= 0
a[e[:email]] += e[:amount]
a
end
=> {
"user_02#yorlook.com" => 17.0,
"user_03#yorlook.com" => 10
}
h = {
data: {
user: {
value: "John Doe"
}
}
}
To assign value to the nested hash, we can use
h[:data][:user][:value] = "Bob"
However if any part in the middle is missing, it will cause error.
Something like
h.dig(:data, :user, :value) = "Bob"
won't work, since there's no Hash#dig= available yet.
To safely assign value, we can do
h.dig(:data, :user)&.[]=(:value, "Bob") # or equivalently
h.dig(:data, :user)&.store(:value, "Bob")
But is there better way to do that?
It's not without its caveats (and doesn't work if you're receiving the hash from elsewhere), but a common solution is this:
hash = Hash.new {|h,k| h[k] = h.class.new(&h.default_proc) }
hash[:data][:user][:value] = "Bob"
p hash
# => { :data => { :user => { :value => "Bob" } } }
And building on #rellampec's answer, ones that does not throw errors:
def dig_set(obj, keys, value)
key = keys.first
if keys.length == 1
obj[key] = value
else
obj[key] = {} unless obj[key]
dig_set(obj[key], keys.slice(1..-1), value)
end
end
obj = {d: 'hey'}
dig_set(obj, [:a, :b, :c], 'val')
obj #=> {d: 'hey', a: {b: {c: 'val'}}}
interesting one:
def dig_set(obj, keys, value)
if keys.length == 1
obj[keys.first] = value
else
dig_set(obj[keys.first], keys.slice(1..-1), value)
end
end
will raise an exception anyways if there's no [] or []= methods.
I found a simple solution to set the value of a nested hash, even if a parent key is missing, even if the hash already exists. Given:
x = { gojira: { guitar: { joe: 'charvel' } } }
Suppose you wanted to include mario's drum to result in:
x = { gojira: { guitar: { joe: 'charvel' }, drum: { mario: 'tama' } } }
I ended up monkey-patching Hash:
class Hash
# ensures nested hash from keys, and sets final key to value
# keys: Array of Symbol|String
# value: any
def nested_set(keys, value)
raise "DEBUG: nested_set keys must be an Array" unless keys.is_a?(Array)
final_key = keys.pop
return unless valid_key?(final_key)
position = self
for key in keys
return unless valid_key?(key)
position[key] = {} unless position[key].is_a?(Hash)
position = position[key]
end
position[final_key] = value
end
private
# returns true if key is valid
def valid_key?(key)
return true if key.is_a?(Symbol) || key.is_a?(String)
raise "DEBUG: nested_set invalid key: #{key} (#{key.class})"
end
end
usage:
x.nested_set([:instrument, :drum, :mario], 'tama')
usage for your example:
h.nested_set([:data, :user, :value], 'Bob')
any caveats i missed? any better way to write the code without sacrificing readability?
Searching for an answer to a similar question I developmentally stumbled upon an interface similar to #niels-kristian's answer, but wanted to also support a namespace definition parameter, like an xpath.
def deep_merge(memo, source)
# From: http://www.ruby-forum.com/topic/142809
# Author: Stefan Rusterholz
merger = proc { |key, v1, v2| Hash === v1 && Hash === v2 ? v1.merge(v2, &merger) : v2 }
memo.merge!(source, &merger)
end
# Like Hash#dig, but for setting a value at an xpath
def bury(memo, xpath, value, delimiter=%r{\.})
xpath = xpath.split(delimiter) if xpath.respond_to?(:split)
xpath.map!{|x|x.to_s.to_sym}.push(value)
deep_merge(memo, xpath.reverse.inject { |memo, field| {field.to_sym => memo} })
end
Nested hashes are sort of like xpaths, and the opposite of dig is bury.
irb(main):014:0> memo = {:test=>"value"}
=> {:test=>"value"}
irb(main):015:0> bury(memo, 'test.this.long.path', 'value')
=> {:test=>{:this=>{:long=>{:path=>"value"}}}}
irb(main):016:0> bury(memo, [:test, 'this', 2, 4.0], 'value')
=> {:test=>{:this=>{:long=>{:path=>"value"}, :"2"=>{:"4.0"=>"value"}}}}
irb(main):017:0> bury(memo, 'test.this.long.path.even.longer', 'value')
=> {:test=>{:this=>{:long=>{:path=>{:even=>{:longer=>"value"}}}, :"2"=>{:"4.0"=>"value"}}}}
irb(main):018:0> bury(memo, 'test.this.long.other.even.longer', 'other')
=> {:test=>{:this=>{:long=>{:path=>{:even=>{:longer=>"value"}}, :other=>{:even=>{:longer=>"other"}}}, :"2"=>{:"4.0"=>"value"}}}}
A more ruby-helper-like version of #niels-kristian answer
You can use it like:
a = {}
a.bury!([:a, :b], "foo")
a # => {:a => { :b => "foo" }}
class Hash
def bury!(keys, value)
key = keys.first
if keys.length == 1
self[key] = value
else
self[key] = {} unless self[key]
self[key].bury!(keys.slice(1..-1), value)
end
self
end
end