Related
Given data:
data = [
{"id":14, "sort":1, "content":"9", foo: "2022"},
{"id":14, "sort":4, "content":"5", foo: "2022"},
{"id":14, "sort":2, "content":"1", foo: "2022"},
{"id":14, "sort":3, "content":"0", foo: "2022"},
{"id":15, "sort":4, "content":"4", foo: "2888"},
{"id":15, "sort":2, "content":"1", foo: "2888"},
{"id":15, "sort":1, "content":"3", foo: "2888"},
{"id":15, "sort":3, "content":"3", foo: "2888"},
{"id":16, "sort":1, "content":"8", foo: "3112"},
{"id":16, "sort":3, "content":"4", foo: "3112"},
{"id":16, "sort":2, "content":"4", foo: "3112"},
{"id":16, "sort":4, "content":"9", foo: "3112"}
]
Got the contents concatenated by their sort and ids with:
formatted = data.group_by { |d| d[:id]}.transform_values do |value_array|
value_array.sort_by { |b| b[:sort] }
.map { |c| c[:content] }.join
end
puts formatted
#=> {14=>"9105", 15=>"3134", 16=>"8449"}
I know that foo exists inside value_array but wondering how can I include foo to exist inside the formatted variable so I can map through it to get the desired output or if it's possible?
Desired Output:
[
{"id":14, "concated_value":"9105", foo: "2022"},
{"id":15, "concated_value":"3134", foo: "2888"},
{"id":16, "concated_value":"8449", foo: "3112"}
]
Since :foo is unique to :id. You can do this as follows:
data.group_by {|h| h[:id]}.map do |_,sa|
sa.map(&:dup).sort_by {|h| h.delete(:sort) }.reduce do |m,h|
m.merge(h) {|key,old,new| key == :content ? old + new : old }
end.tap {|h| h[:concated_value] = h.delete(:content) }
end
#=> [
# {"id":14, foo: "2022", "concated_value":"9105"},
# {"id":15, foo: "2888", "concated_value":"3134"},
# {"id":16, foo: "3112", "concated_value":"8449"}
# ]
First we group by id. group_by {|h| h[:id]}
Then we dup the hashes in the groups (so as not to destory the original). map(&:dup)
Then we sort by sort and delete it at the same time. .sort_by {|h| h.delete(:sort) }
Then we merge the groups together and concatenate the content key only.
m.merge(h) {|key,old,new| key == :content ? old + new : old }
Then we just change the key for content to concated_value tap {|h| h[:concated_value] = h.delete(:content) }
We can use first value from value_array to get our :id & :foo values
formatted = data.group_by { |d| d[:id]}.values.map do |value_array|
concated_value = value_array.sort_by { |b| b[:sort] }
.map { |c| c[:content] }.join
value_array.first.slice(:id, :foo)
.merge concated_value: concated_value
end
I think this is a good usecase for reduce, since after grouping you need first to get rid of the ID in the resulting [ID, VALUES] array from group_by and just return a reduced version of the VALUES part - this can all be done without any ActiveSupport etc. dependencies:
data
.group_by{ |d| d[:id] } # Get an array of [ID, [VALUES]]
.reduce([]) do |a, v| # Reduce it into a new empty array
# Append a new hash to the new array
a << {
id: v[1].first[:id], # Just take the ID of the first entry
foo: v[1].first[:foo], # Dito for foo
concatenated: v[1]
.sort_by{ |s| s[:sort] } # now sort all hashes by its sort key
.collect{ |s| s[:content] } # collect the content
.join # and merge it into a string
}
end
Output:
[{:id=>14, :foo=>"2022", :concatenated=>"9105"},
{:id=>15, :foo=>"2888", :concatenated=>"3134"},
{:id=>16, :foo=>"3112", :concatenated=>"8449"}]
EDIT
I had some other approach in mind when i started to write the previous solution, reduce was not really necessary, since the size of the array after group_by does not change, so a map is sufficient.
But while rewriting the code, i was thinking that creating a new hash with all the keys and copying all the values from the first hash within VALUES was a bit too much work, so it would be easier to just reject the overhead keys:
keys_to_ignore = [:sort, :content]
data
.group_by{ |d| d[:id] } # Get an array of [ID, [VALUES]]
.map do |v|
v[1]
.first # Take the first hash from [VALUES]
.merge({'concatenated': v[1] # Insert the concatenated values
.sort_by{ |s| s[:sort] } # now sort all hashes by its sort key
.collect{ |s| s[:content] } # collect the content
.join # and merge it into a string
})
.select { |k, _| !keys_to_ignore.include? k }
end
Output
[{:id=>14, :foo=>"2022", :concatenated=>"9105"},
{:id=>15, :foo=>"2888", :concatenated=>"3134"},
{:id=>16, :foo=>"3112", :concatenated=>"8449"}]
Online demo here
This will work even without Rails:
$irb> formatted = []
$irb> data.sort_by!{|a| a[:sort]}.map {|z| z[:id]}.uniq.each_with_index { |id, index| formatted << {id: id, concated_value: data.map{|c| (c[:id] == id ? c[:content] : nil)}.join, foo: data[index][:foo]}}
$irb> formatted
[{:id=>14, :concated_value=>"9105", :foo=>"2022"},
{:id=>15, :concated_value=>"3134", :foo=>"2888"},
{:id=>16, :concated_value=>"8449", :foo=>"3112"}]
data.sort_by { |h| h[:sort] }.
each_with_object({}) do |g,h| h.update(g[:id]=>{ id: g[:id],
concatenated_value: g[:content].to_s, foo: g[:foo] }) { |_,o,n|
o.merge(concatenated_value: o[:concatenated_value]+n[:concatenated_value]) }
end.values
#=> [{:id=>14, :concatenated_value=>"9105", :foo=>"2022"},
# {:id=>15, :concatenated_value=>"3134", :foo=>"2888"},
# {:id=>16, :concatenated_value=>"8449", :foo=>"3112"}]
This uses the form of Hash#update (aka merge!) that employs a block to determine the values of keys (here the value of :id) that are present in both hashes being merged. See the doc for the description of the three block variables (here _, o and n).
Note the receiver of values (at the end) is the following.
{ 14=>{ :id=>14, :concatenated_value=>"9105", :foo=>"2022" },
15=>{ :id=>15, :concatenated_value=>"3134", :foo=>"2888" },
16=>{ :id=>16, :concatenated_value=>"8449", :foo=>"3112" } }
In my code I want to use string interpolation for an email subject I am generating.
output = "this is my %{title}" % {title: "Text here"}
This works as expected, but is there a way to use hashes inside of hashes and still be able to use string interpolation?
It would be awesome if I could do something like:
output = "this is my %{title.text}" % {title: {text: "text here"}}
In Ruby 2.3, sprintf checks the hash's default value, so you could provide a default_proc to dig up the nested value:
hash = {title: {text: "text here"}}
hash.default_proc = proc { |h, k| h.dig(*k.to_s.split('.').map(&:to_sym)) }
"this is my %{title.text}" % hash
#=> "this is my text here"
Kind of hacky, but it seems to work.
I don't think this is possible with % method. You'd have to use regular Ruby interpolation with "#{}".
I'd also point out that you can use OpenStruct.
title = OpenStruct.new(text: 'text here')
output = "this is my #{title.text}"
It's actually not hard to make this work if you write a simple utility method to "squash" a nested Hash's keys, e.g.:
def squash_hash(hsh, stack=[])
hsh.reduce({}) do |res, (key, val)|
next_stack = [ *stack, key ]
if val.is_a?(Hash)
next res.merge(squash_hash(val, next_stack))
end
res.merge(next_stack.join(".").to_sym => val)
end
end
hsh = { foo: { bar: 1, baz: { qux: 2 } }, quux: 3 }
p squash_hash(hsh)
# => { :"foo.bar" => 1, :"foo.baz.qux" => 2, :quux => 3 }
puts <<END % squash_hash(hsh)
foo.bar: %{foo.bar}
foo.baz.qux: %{foo.baz.qux}
quux: %{quux}
END
# => foo.bar: 1
# foo.baz.qux: 2
# quux: 3
I have one array and i want to match value of id key with other array of hash in multidimensional array,
input = [
[ {"id"=>"1","name"=>"a"},
{"id"=>"2","name"=>"b"},
{"id"=>"3","name"=>"c"},
{"id"=>"4","name"=>"d"},
{"id"=>"5","name"=>"e"},
{"id"=>"6","name"=>"f"}
],
[ {"id"=>"3","hoby"=>"AA"},
{"id"=>"3","hoby"=>"BB"},
{"id"=>"1","hoby"=>"CC"},
{"id"=>"1","hoby"=>"DD"},
{"id"=>"4","hoby"=>"EE"}
],
[ {"id"=>"1","language"=>"A"},
{"id"=>"1","language"=>"B"},
{"id"=>"2","language"=>"B"},
{"id"=>"2","language"=>"C"},
{"id"=>"6","language"=>"D"}
]
]
I need array output like,
output = [
{"id"=>"1","name"=>"a","id"=>"1","hoby"=>"CC","id"=>"1","language"=>"A","id"=>"1","language"=>"B"},
{"id"=>"2","name"=>"b","id"=>"2","language"=>"B"},
{"id"=>"3","name"=>"c","id"=>"3","hoby"=>"AA","id"=>"3","hoby"=>"BB"},
{"id"=>"4","name"=>"d","id"=>"4","hoby"=>"EE"},
{"id"=>"5","name"=>"e"},
{"id"=>"6","name"=>"f","id"=>"6","language"=>"D"}
]
I have wrote code for this,
len = input.length - 1
output = []
input[0].each do |value,index|
for i in 1..len
input[i].each do |j|
if value["id"] == j["id"]
output << value.merge(j)
end
end
end
end
But i am getting wrong output array.There might be any number of sub array in multidimensional array.
Thank,
First of all - it is impossible to have two elements in a hash with the same key. When assigning the value to some key will make the next assignment of the same key with new value override the previous one.
Let's consider the example:
hash = {}
hash["id"] = 1
hash["id"] = 3
hash["id"] = 5
What output for hash["id"] would you expect? 1, 3, 5 or maybe [1, 3, 5]? The way the Hash in ruby works it will output 5, because this is the last assignment to unique key.
Having said that, it is impossible to store multiple occurrences in your hash, but you can try processing it with something like:
input.flatten
.group_by { |h| h["id"] }
.map do |k, a|
a.each_with_object({}) { |in_h, out_h| out_h.merge!(in_h) }
end
Which will result with hash like:
[{"id"=>"1", "name"=>"a", "hoby"=>"DD", "language"=>"B"},
{"id"=>"2", "name"=>"b", "language"=>"C"},
{"id"=>"3", "name"=>"c", "hoby"=>"BB"},
{"id"=>"4", "name"=>"d", "hoby"=>"EE"},
{"id"=>"5", "name"=>"e"},
{"id"=>"6", "name"=>"f", "language"=>"D"}]
Well, it is not the hash as you would expect, but at least it might put you in some direction.
Hope that helps!
maybe this can help you.
input = [
[
{"id"=>"1","name"=>"a"},
{"id"=>"2","name"=>"b"},
{"id"=>"3","name"=>"c"},
{"id"=>"4","name"=>"d"},
{"id"=>"5","name"=>"e"},
{"id"=>"6","name"=>"f"}
],
[
{"id"=>"3","hoby"=>"AA"},
{"id"=>"3","hoby"=>"BB"},
{"id"=>"1","hoby"=>"CC"},
{"id"=>"1","hoby"=>"DD"},
{"id"=>"4","hoby"=>"EE"}
],
[
{"id"=>"1","language"=>"A"},
{"id"=>"1","language"=>"B"},
{"id"=>"2","language"=>"B"},
{"id"=>"2","language"=>"C"},
{"id"=>"6","language"=>"D"}
]
]
This way you can make your "sort" results.
output = {}
input.flatten.each do |h|
output[h["id"]] = {} unless output[h["id"]]
output[h["id"]].merge!(h)
end
output.values
# => [
# => {"id"=>"1", "name"=>"a", "hoby"=>"DD", "language"=>"B"},
# => {"id"=>"2", "name"=>"b", "language"=>"C"},
# => {"id"=>"3", "name"=>"c", "hoby"=>"BB"},
# => {"id"=>"4", "name"=>"d", "hoby"=>"EE"},
# => {"id"=>"5", "name"=>"e"},
# => {"id"=>"6", "name"=>"f", "language"=>"D"}
# => ]
But the better way is use Hash in input. You can define input like hash and "id" like key so if you generate the data, you dont have problem to sort it.
Someting like this
{
"1" => {"name" => "a", "hoby" => "DD", "language" => "B"}
}
I need to bring an array of ruby objects in JSON. I will need to find the item in the JSON object by id, so I think it is best that the id is the key of each object. This structure makes the most sense to me:
{
"1": {"attr1": "val1", "attr2": "val2"},
"2": {"attr1": "val1", "attr2": "val2"},
"3": {"attr1": "val1", "attr2": "val2"}
}
That way I can easily call into the json object like console.log(json_obj[id].attr1)
The issue is that I am not quite sure how to build this in ruby. This is as far as I have gotten:
# in ruby
#book_types = []
BookType.all.each do |bt|
#book_types << {bt.id => {:attr => bt.attr}}
end
#book_types = #book_types.to_json
// In JS
var bookTypes = JSON.parse('<%=raw #book_types %>');
2 questions: How can I build this in ruby? Is there a better way to accomplish what I am doing?
Also just a note that I am building this on the Rails framework
Thanks!
Assuming BookType is an ActiveRecord class, you can just do this:
BookType.all(:select => "attr1, attr2").to_json
...where "attr1, attr2" is a list of the attributes you want to include in your JSON.
If you want the ids as keys, you can do this instead:
BookType.all.inject({}) { |hsh, bt|
hsh[bt.id] = { "attr1" => bt.attr1, "attr2" => bt.attr2 }
hsh
}.to_json
I am wondering what is the best way to convert a json formatted key value pair to ruby hash with symbol as key:
example:
{ 'user': { 'name': 'foo', 'age': 40, 'location': { 'city' : 'bar', 'state': 'ca' } } }
==>
{ :user=>{ :name => 'foo', :age =>'40', :location=>{ :city => 'bar', :state=>'ca' } } }
Is there a helper method can do this?
using the json gem when parsing the json string you can pass in the symbolize_names option. See here: http://flori.github.com/json/doc/index.html (look under parse)
eg:
>> s ="{\"akey\":\"one\",\"bkey\":\"two\"}"
>> JSON.parse(s,:symbolize_names => true)
=> {:akey=>"one", :bkey=>"two"}
Leventix, thank you for your answer.
The Marshal.load(Marshal.dump(h)) method probably has the most integrity of the various methods because it preserves the original key types recursively.
This is important in case you have a nested hash with a mix of string and symbol keys and you want to preserve that mix upon decode (for instance, this could happen if your hash contains your own custom objects in addition to highly complex/nested third-party objects whose keys you cannot manipulate/convert for whatever reason, like a project time constraint).
E.g.:
h = {
:youtube => {
:search => 'daffy', # nested symbol key
'history' => ['goofy', 'mickey'] # nested string key
}
}
Method 1: JSON.parse - symbolizes all keys recursively => Does not preserve original mix
JSON.parse( h.to_json, {:symbolize_names => true} )
=> { :youtube => { :search=> "daffy", :history => ["goofy", "mickey"] } }
Method 2: ActiveSupport::JSON.decode - symbolizes top-level keys only => Does not preserve original mix
ActiveSupport::JSON.decode( ActiveSupport::JSON.encode(h) ).symbolize_keys
=> { :youtube => { "search" => "daffy", "history" => ["goofy", "mickey"] } }
Method 3: Marshal.load - preserves original string/symbol mix in the nested keys. PERFECT!
Marshal.load( Marshal.dump(h) )
=> { :youtube => { :search => "daffy", "history" => ["goofy", "mickey"] } }
Unless there is a drawback that I'm unaware of, I'd think Method 3 is the way to go.
Cheers
There isn't anything built in to do the trick, but it's not too hard to write the code to do it using the JSON gem. There is a symbolize_keys method built into Rails if you're using that, but that doesn't symbolize keys recursively like you need.
require 'json'
def json_to_sym_hash(json)
json.gsub!('\'', '"')
parsed = JSON.parse(json)
symbolize_keys(parsed)
end
def symbolize_keys(hash)
hash.inject({}){|new_hash, key_value|
key, value = key_value
value = symbolize_keys(value) if value.is_a?(Hash)
new_hash[key.to_sym] = value
new_hash
}
end
As Leventix said, the JSON gem only handles double quoted strings (which is technically correct - JSON should be formatted with double quotes). This bit of code will clean that up before trying to parse it.
Recursive method:
require 'json'
def JSON.parse(source, opts = {})
r = JSON.parser.new(source, opts).parse
r = keys_to_symbol(r) if opts[:symbolize_names]
return r
end
def keys_to_symbol(h)
new_hash = {}
h.each do |k,v|
if v.class == String || v.class == Fixnum || v.class == Float
new_hash[k.to_sym] = v
elsif v.class == Hash
new_hash[k.to_sym] = keys_to_symbol(v)
elsif v.class == Array
new_hash[k.to_sym] = keys_to_symbol_array(v)
else
raise ArgumentError, "Type not supported: #{v.class}"
end
end
return new_hash
end
def keys_to_symbol_array(array)
new_array = []
array.each do |i|
if i.class == Hash
new_array << keys_to_symbol(i)
elsif i.class == Array
new_array << keys_to_symbol_array(i)
else
new_array << i
end
end
return new_array
end
Of course, there is a json gem, but that handles only double quotes.
Another way to handle this is to use YAML serialization/deserialization, which also preserves the format of the key:
YAML.load({test: {'test' => { ':test' => 5}}}.to_yaml)
=> {:test=>{"test"=>{":test"=>5}}}
Benefit of this approach it seems like a format that is better suited for REST services...
The most convenient way is by using the nice_hash gem: https://github.com/MarioRuiz/nice_hash
require 'nice_hash'
my_str = "{ 'user': { 'name': 'foo', 'age': 40, 'location': { 'city' : 'bar', 'state': 'ca' } } }"
# on my_hash will have the json as a hash
my_hash = my_str.json
# or you can filter and get what you want
vals = my_str.json(:age, :city)
# even you can access the keys like this:
puts my_hash._user._location._city
puts my_hash.user.location.city
puts my_hash[:user][:location][:city]
If you think you might need both string and symbol keys:
JSON.parse(json_string).with_indifferent_access