error: Json parsing in ruby - ruby-on-rails

file= File.read('customers.json')
data_hash= JSON.parse( file)
# id=data_hash['customers'].map { |x| x['id'] }
data_hash['customers']['user_id'].each do |user|
latitude=user['customers']['latitude']
puts latitude
end
what error I am facing?
no implicit conversion of String into Integer (TypeError)
below is my json file
{
"customers" :[
{"latitude": "12.986375", "user_id": "12", "name": "Chris", "longitude": "77.043701"},
{"latitude": "11.92893", "user_id": "1", "name": "Alice", "longitude": "78.27699"},
{"latitude": "11.8856167", "user_id": "2", "name": "Ian", "longitude": "78.4240911"}
]
}

If you are trying to get latitude or something you should do it like:
file = File.read('customers.json')
data_hash = JSON.parse(file)
data_hash["customers"].each do |user|
latitude = user["latitude"]
puts latitude
end
OUTPUT:
12.986375
11.92893
11.8856167

The no implicit conversion of String into Integer (TypeError) error occurs when you try to treat an array as a hash. Since arrays expect integer keys for indexing Ruby will try to implicitly cast whatever gets passed to [] to an integer:
[]['a']
TypeError: no implicit conversion of String into Integer
In your case it's the data_hash['customers'] node that's an array.
You can actually just iterate through each item in data_hash[customers] mapping the value for the :latitude key back to an array via map.
puts data_hash["customers"].map { |h| h["latitude"] }

Related

How to change hash key from array of hashes in ruby?

Given:
data = [
{"votable_id"=>1150, "user_ids"=>"1,2,3,4,5,6,"},
{"votable_id"=>1151, "user_ids"=>"55,66,34,23,56,7,8"}
]
This is the expected result. Array should have first 5 elements.
data = [
{"votable_id"=>1150, "user_ids"=>["1","2","3","4","5"]},
{"votable_id"=>1151, "user_ids"=>["55","66","34","23","56","7",8"]}
]
This is what I tried :
data.map{|x| x['user_ids'] = x['user_ids'].split(',').first(5)}
Any other optimized solution ?
You can also use .map and .tap like this
data.map do |h|
h.tap { |m_h| m_h["user_ids"]= m_h["user_ids"].split(',').first(5)}
end
data = [
{"votable_id"=>1150, "user_ids"=>"1,2,3,4,5,6,"},
{"votable_id"=>1151, "user_ids"=>"55,66,34,23,56,7,8"}
]
Code
h=data.map do |h|
h["user_ids"]=[h["user_ids"].split(',').first(5)].flatten
h
end
p h
Output
[{"votable_id"=>1150, "user_ids"=>["1", "2", "3", "4", "5"]}, {"votable_id"=>1151, "user_ids"=>["55", "66", "34", "23", "56"]}]
data.map { |h| h.merge("user_ids"=>h["user_ids"].split(',').first(5)) }
#=> [{"votable_id"=>1150, "user_ids"=>["1", "2", "3", "4", "5"]},
# {"votable_id"=>1151, "user_ids"=>["55", "66", "34", "23", "56"]}]
See Hash#merge. This leaves data unchanged. To modify (or mutate) data use Hash#merge! (aka update). h.merge(k=>v) is a shortcut for h.merge({ k=>v }).

More efficient method than string replace with ruby gsub

I have a third party JSON feed which is huge - lots of data. Eg
{
"data": [{
"name": "ABC",
"price": "2.50"
},
...
]
}
I am required to strip the quotation marks from the price as the consumer of the JSON feed requires it in this way.
To do this I am performing a regex to find the prices and then iterating over the prices and doing a string replace using gsub. This is how I am doing it:
price_strings = json.scan(/(?:"price":")(.*?)(?:")/).uniq
price_strings.each do |price|
json.gsub!("\"#{price.reduce}\"", price.reduce)
end
json
The main bottle neck appears to be on the each block. Is there a better way of doing this?
If this JSON string is going to be serialised into a Hash at some point in your application or in another 3rd-party dependency of your code (i.e. to be consumed by your colleagues or modules), I suggest negotiating with them to convert the price value from String to Numeric on demand when the json is already a Hash, as this is more efficient, and allows them to...
...handle edge-case where say if "price": "" of which my code below will not work, as it would remove the "", and will be a JSON syntax error.
However, if you do not have control over this, or are doing once-off mutation for the whole json data, then can you try below?
json =
<<-eos
{
"data": [{
"name": "ABC",
"price": "2.50",
"somethingsomething": {
"data": [{
"name": "DEF",
"price": "3.25", "someprop1": "hello",
"someprop2": "world"
}]
},
"somethinggggg": {
"price": "123.45" },
"something2222": {
"price": 9.876, "heeeello": "world"
}
}]
}
eos
new_json = json.gsub /("price":.*?)"(.*?)"(.*?,|})/, '\1\2\3'
puts new_json
# =>
# {
# "data": [{
# "name": "ABC",
# "price": 2.50,
# "somethingsomething": {
# "data": [{
# "name": "DEF",
# "price": 3.25, "someprop1": "hello",
# "someprop2": "world"
# }]
# },
# "somethinggggg": {
# "price": 123.45 },
# "something2222": {
# "price": 9.876, "heeeello": "world"
# }
# }]
# }
DISCLAIMER: I am not a Regexp expert.
This is truly a fools errand.
JSON.parse('{ "price": 2.50 }')
> {price: 2.5}
As you can see from this javascript example the parser on the consuming side will truncate the float to whatever it wants.
Use a string if you want to provide a formatted number or leave formatting up to the client.
In fact using floats to represent money is widely known as a really bad idea since floats and doubles cannot accurately represent the base 10 multiples that we use for money. JSON only has a single number type that represents both floats and integers.
If the client is going to do any kind of calculations with the value you should use an integer in the lowest monetary denomation (cents for euros and dollars) or a string that's interpreted as a BigDecimal equivilent type by the consumer.

Ruby Grape: How to send array of hashes as param

I sends an array of hashes.
[{question_id: 1_id, answer:1_String},{question_id: 2_id, answer:2_String}]
and I used this code in my API file:
requires :profile_setting, type: Array[Hash], desc: "[{question_id: 1_id, answer: '1_String'},{question_id: 2_id, answer: '2_String'}]"
params: [{question_id: 1_id, answer:1_String},{question_id: 2_id, answer:2_String}]
response:
{
"error": "profile_setting is invalid"
}
how to send a Array of multiple hashes.
Your JSON misses quotes around keys and values.
Should be
[{
"question_id": "1 _id",
"answer": "1 _String"
},
{
"question_id": "2 _id",
"answer": "2 _String"
}]

extracting hash data in ruby on rails

I'm working with sabre api ( test licence ) in my rails application,
i get a JSON response and when I parse it a get this hash
{
"OriginLocation"=>"DEN",
"Destinations"=>[
{
"Rank"=>1,
"Destination"=>{
"DestinationLocation"=>"LAX",
"AirportName"=>"Los Angeles International Airport",
"CityName"=>"Los Angeles",
"CountryCode"=>"US",
"CountryName"=>"United States",
"RegionName"=>"North America",
"Type"=>"Airport"
}
},
{
"Rank"=>2,
"Destination"=>{
"DestinationLocation"=>"LAS",
"AirportName"=>"McCarran International Airport",
"CityName"=>"Las Vegas",
"CountryCode"=>"US",
"CountryName"=>"United States",
"RegionName"=>"North America",
"Type"=>"Airport"
}
},
{
"Rank"=>3,
"Destination"=>{
"DestinationLocation"=>"CHI",
"CountryCode"=>"US",
"CountryName"=>"United States",
"RegionName"=>"North America",
"MetropolitanAreaName"=>"Chicago",
"Links"=>[
{
"rel"=>"airportsInCity",
"href"=>"https://api.test.sabre.com/v1/lists/supported/cities/CHI/airports"
}
],
"Type"=>"City"
}
}
...
}
How can i extract the data (ex: destination) information from it?
I tried this code but i get an error " undefined method ``each' for nil:NilClass "
#hash['Destinations'].each do |key, value|
puts key
value.each do |k,v|
puts k
puts v
end
end
Even though you've specified key and value, only key is populated (with the entire hash data), and value is nil. That's why you're getting an error.
Assuming you're on Ruby 2.3 or above, I suggest you use something like this instead:
#hash['Destinations'].map { |d| d.dig('Destination', 'CityName') }
#=> ["Los Angeles", "Las Vegas", nil]
You can read up more on dig here. It's useful for this kind of deeply nested data, and will protect you from keys that don't exist (and return nil instead); as long as you don't mix its usage on arrays and hashes.

Search a JSON Response using Ruby

I'm using a Ruby script to interface with an application API and the results being returned are in a JSON format. For example:
{
"incidents": [
{
"number": 1,
"status": "open",
"key": "abc123"
}
{
"number": 2,
"status": "open",
"key": "xyz098"
}
{
"number": 3,
"status": "closed",
"key": "lmn456"
}
]
}
I'm looking to search each block for a particular "key" value (yzx098 in this example) and return the associated "number" value.
Now, I'm very new to Ruby and I'm not sure if there's already a function to help accomplish this. However, a couple days of scouring the Googles and Ruby resource books hasn't yielded anything that works.
Any suggestions?
First of all, the JSON should be as below: (note the commas)
{
"incidents": [
{
"number": 1,
"status": "open",
"key": "abc123"
},
{
"number": 2,
"status": "open",
"key": "xyz098"
},
{
"number": 3,
"status": "closed",
"key": "lmn456"
}
]
}
Strore the above json in a variable
s = '{"incidents": [{"number": 1,"status": "open","key": "abc123"},{"number": 2,"status": "open","key": "xyz098"},{"number": 3,"status": "closed","key": "lmn456"}]}'
Parse the JSON
h = JSON.parse(s)
Find the required number using map
h["incidents"].map {|h1| h1['number'] if h1['key']=='xyz098'}.compact.first
Or you could also use find as below
h["incidents"].find {|h1| h1['key']=='xyz098'}['number']
Or you could also use select as below
h["incidents"].select {|h1| h1['key']=='xyz098'}.first['number']
Do as below
# to get numbers from `'key'`.
json_hash["incidents"].map { |h| h['key'][/\d+/].to_i }
json_hash["incidents"] - will give you the value of the key "incidents", which is nothing but an array of hash.
map to iterate thorough each hash and collect the value of 'key'. Then applying Hash#[] to each inner hash of the array, to get the value of "key". Then calling str[regexp], to get only the number strings like '098' from "xyz098", finally applying to_i to get the actual integer from it.
If the given hash actually a json string, then first parse it using JSON::parse to convert it to a hash.Then do iterate as I said above.
require 'json'
json_hash = JSON.parse(json_string)
# to get values from the key `"number"`.
json_hash["incidents"].map { |h| h['number'] } # => [1, 2, 3]
# to search and get all the numbers for a particular key match and take the first
json_hash["incidents"].select { |h| h['key'] == 'abc123' }.first['number'] # => 1
# or to search and get only the first number for a particular key match
json_hash["incidents"].find { |h| h['key'] == 'abc123' }['number'] # => 1

Resources