I have a function return_summoner_champion_list(name) that will return the following JSON data when called
[
{
"id"=>"1",
"name"=>"A"
},
{
"id"=>"2",
"name"=>"B"
},
and so on...
]
How do I iterate through the JSON array and print out all ids?
I tried
return_summoner_champion_list(name).each do |list|
puts list["id"]
end
but it still returns the same JSON data as above without any changes.
I think you're looking for Array#collect not Array#each:
return_summoner_champion_list(name).collect{|l| l['id']}
=> [1,2, ...]
Is your method returning JSON or an Ruby array? If it is indeed returning JSON, first convert that to an array with JSON.parse(), and then work with the array that is returned.
Related
I got a jbuilder response like below
{
"name": "amb_devcernerpowerchart_com:patient_val2",
"value": "{\"value\"=>\"patient_value\", \"expiration\"=>31536000, \"created_datetime\"=>\"2019-12-09T12:09:59Z\"}"
}
I want to only value part of value i.e i want output like below.
{
"name": "amb_devcernerpowerchart_com:patient_val2",
"value": "value"=>"patient_value"
}
How do i get this?
Jbuilder file looks like this
json.name #component.preference_data.id
json.value #component.preference_data.value
From the question, it seems as though the data that you are receiving in the value field is a stringified JSON. You would have to parse the JSON and retrieve the required value as follows:
json.value JSON.parse(#component.preference_data.value)['value']
Basically, #component.preference_data.value returns a string, which is parsed into a JSON using JSON.parse. At the end of that, we get a hash whose 'value' field is retrieved.
I receive (similar to) the following JSON data:
{"accountId"=>"some-private-really-long-account-id",
"stats"=>
{"score"=>
{"globalScore"=>
[{"key"=>"lifetimeScore", "value"=>"571",
"key"=>"someOtherKeyHere", "value"=>"someValue"}]}
I am not quite sure how I would get the lifetime score. I've tried doing stuff like this:
puts data["globalScore"]["lifetimeScore"]["value"]
But that doesn't work. (data is of course the JSON data received).
I believe the problem here is that data["globalScore"]["lifetimeScore"]["value"] doesn't reference a valid "path" within the JSON. Better formatting helps to clarify this:
hash = {
"accountId" => "some-private-really-long-account-id",
"stats" => {
"score" => {
"globalScore" => [
{
"key" => "lifetimeScore",
"value" => "571",
"key" => "someOtherKeyHere",
"value" => "someValue"
}
]
}
}
}
This Ruby hash has some issues since a hash can't actually have multiple values for a given key, but that aside,
hash['stats']['score']['globalScore'][0]['value']
is a perfectly valid way to access the 'value' field.
My point is that the problem with the original question is not that hash#dig(...) should be used (as shown by #Phlip), it is that the "path" through the Hash data structure was actually invalid.
hash.dig("globalScore", "lifetimeScore", "value)
will fail just like the bracketed syntax in the original question.
Use JSON.parse(body) to convert your json to a hash. Then use hash.dig('stats', 'score', 'globalScore', 0, 'value') to run queries on that hash.
So I am iterating through a set of data and building a hash from it:
clean_response = Array.new
response.each_with_index do |h, idx|
clean_response <<
{
:lat => h["location"]["latitude"],
:lg => h["location"]["longitude"],
:place => h["location"]["name"],
#This grabs the entire hash at "location" because we are wanting all of that data
:profile_picture => h["user"]["profile_picture"],
:hash_tags => h["tags"],
:username => h["user"]["username"],
:fullname => h["user"]["full_name"],
:created_time => (Time.at(h["created_time"].to_i)).to_s,
:image => h["images"]["low_resolution"]["url"] # we can replace this with whichever resolution.
}
end
Which return an array of hashes like so:
[{:lat=>40.7486382,
:lg=>-73.9487686,
:place=>"The Cliffs at LIC",
:profile_picture=>"http://scontent.cdninstagram.com/hphotos-xaf1/t51.2885-19/s150x150/12104940_1653775014895036_286845624_a.jpg",
:hash_tags=>["bouldering"],
:username=>"denim_climber",
:fullname=>"DenimClimber",
:created_time=>2015-10-13 22:58:09 -0400,
:image=>"https://scontent.cdninstagram.com/hphotos-xaf1/t51.2885-15/s320x320/e35/11856571_1062082890510188_611068928_n.jpg"},
{:lat=>40.7459602,
:lg=>-73.9574966,
:place=>"SHI",
:profile_picture=>"http://scontent.cdninstagram.com/hphotos-xaf1/t51.2885-19/11348212_1453525204954535_631200718_a.jpg",
:hash_tags=>["cousins", "suchafunmoment", "johnlennonstyle"],
:username=>"xiomirb",
:fullname=>"Xiomi",
:created_time=>2015-10-13 22:57:21 -0400,
:image=>"https://scontent.cdninstagram.com/hphotos-xaf1/t51.2885-15/s320x320/e35/11375290_1688934151392424_2009781937_n.jpg"}]
I'd like to convert this data to json and then serve it to a specific view.
How can I convert this? I tried the .to_json method but it doesn't return a well formatted one since my UI isn't binding to the data.
You can convert a Ruby hash into JSON using to_json:
require 'json'
your_hash.to_json # gives you a JSON object
But, in your case the data is an array of hashes, but NOT a hash. So, your to_json would not work.
I am not quite sure how you want to do this, but one possibility is to loop through the array of hashes, get each hash and convert that to a JSON object using to_json call (like shown above) and build a new array of JSON objects. This way, you can build an array of JSON objects from an array of hashes.
array_of_json = []
# loop through the array of hashes
clean_response.each do |hash|
array_of_json << hash.to_json
end
array_of_json # array of JSON objects
If by "serve it to a specific view" you mean pass it to a .haml or .erb template, you can pass the array of hashes as is. Both haml and erb will allow you to iterate over the array, and even the hash if you want.
If you mean you want to hand a json string to the browser, #to_json should work fine. Other options are jbuilder or oat when you want to refine what is sent, but to_json should "serve" you well!
TL;DR:
How can i use jbuilder to create JSON that looks like this?
[
{}, // Your new pagination state
[{}, ...] // An array of JSON objects
]
Longer version:
I am trying get pagination working with Backbone.js and backbone-pageable https://github.com/wyuenho/backbone-pageable .
Backbone-pageable requires that the JSON returned be formatted such that it's an array of two objects. The first object is a regular object containing pagination control information. The second object should be an array of your actual data formatted as Backbone would normally expect. These expectations are hard coded into backbone-pageable's parse methods (source)
It seems weird to have an array of un-like items but for this use case it seems acceptable.
For json i've used rabl in the past but for science I'm trying to use jbuilder and I've gotten this far...
JSON structure (wrong):
{
"current_page": 1,
"total_pages": 6,
...,
"entries": [
{ "id": 131 },
...
]
}
Using this code:
json.current_page #posts.current_page
...
json.entries #posts do |post|
json.extract! post, :id...
end
Closer, but still very wrong :/
Thank you
Can you try this:
json.array! [0,1] do |index|
if index == 0
json.current_page #posts.current_page
...
else
json.entries #posts do |post|
json.extract! post, :id...
end
end
end
Lets say I have this Hash:
{
:info => [
{
:from => "Ryan Bates",
:message => "sup bra",
:time => "04:35 AM"
}
]
}
I can call the info array by doing hash[:info].
Now when I turn this into JSON (JSON.generate), and then parse it (JSON.parse), I get this hash:
{
"info" => [
{
"from" => "Ryan Bates",
"message" => "sup bra",
"time" => "04:35 AM"
}
]
}
Now if I use hash[:info] it returns nil, but not if I use hash["info"].
Why is this? And is there anyway to fix this incompatibility (besides using string keys from the start)?
The JSON generator converts symbols to strings because JSON does not support symbols. Since JSON keys are all strings, parsing a JSON document will produce a Ruby hash with string keys by default.
You can tell the parser to use symbols instead of strings by using the symbolize_names option.
Example:
original_hash = {:info => [{:from => "Ryan Bates", :message => "sup bra", :time => "04:35 AM"}]}
serialized = JSON.generate(original_hash)
new_hash = JSON.parse(serialized, {:symbolize_names => true})
new_hash[:info]
#=> [{:from=>"Ryan Bates", :message=>"sup bra", :time=>"04:35 AM"}]
Reference: http://www.ruby-doc.org/stdlib-1.9.3/libdoc/json/rdoc/JSON.html#method-i-parse
In short, no. Think about it this way, storing symbols in JSON is the same as storing strings in JSON. So you cannot possibly distinguish between the two when it comes to parsing the JSON string. You can of course convert the string keys back into symbols, or in fact even build a class to interact with JSON which does this automagically, but I would recommend just using strings.
But, just for the sake of it, here are the answers to this question the previous times it's been asked:
what is the best way to convert a json formatted key value pair to ruby hash with symbol as key?
ActiveSupport::JSON decode hash losing symbols
Or perhaps a HashWithIndifferentAccess
I solved my similar issue with calling the with_indifferent_access method on it
Here I have a json string and we can assign it to variable s
s = "{\"foo\":{\"bar\":\"cool\"}}"
So now I can parse the data with the JSON class and assign it to h
h = JSON.parse(s).with_indifferent_access
This will produce a hash that can accept a string or a symbol as the key
h[:foo]["bar"]
#=> "cool"
Use ActiveSupport::JSON.decode, it will allow you to swap json parsers easier
Use ActiveSupport::JSON.decode(my_json, symbolize_names: true)
This will recursively symbolize all keys in the hash.
(confirmed on ruby 2.0)
It's possible to modify all the keys in a hash to convert them from a string to a symbol:
symbol_hash = Hash[obj.map{ |k,v| [k.to_sym, v] }]
puts symbol_hash[:info]
# => {"from"=>"Ryan Bates", "message"=>"sup bra", "time"=>"04:35 AM"}
Unfortunately that doesn't work for the hash nested inside the array. You can, however, write a little recursive method that converts all hash keys:
def symbolize_keys(obj)
#puts obj.class # Useful for debugging
return obj.collect { |a| symbolize_keys(a) } if obj.is_a?(Array)
return obj unless obj.is_a?(Hash)
return Hash[obj.map{ |k,v| [k.to_sym, symbolize_keys(v)] }]
end
symbol_hash = symbolize_keys(hash)
puts symbol_hash[:info]
# => {:from=>"Ryan Bates", :message=>"sup bra", :time=>"04:35 AM"}
You can't use that option like this
ActiveSupport::JSON.decode(str_json, symbolize_names: true)
In Rails 4.1 or later, ActiveSupport::JSON.decode no longer accepts
an options hash for MultiJSON. MultiJSON reached its end of life and
has been removed.
You can use symbolize_keys to handle it.
Warning: It works only for JSON strings parsed to hash.
ActiveSupport::JSON.decode(str_json).symbolize_keys