I'm using the dashing dashboard to display some data. Part of my code for one of the jobs uses the map! function in ruby:
vars = arr.map! { |element| element.gsub(/.{3}$/, '' )}
and when I try to run the dashboard using dashing start, I get the following error :
scheduler caught exception:
undefined method map! for #<Hash: 0x......>
If I run the code on its own as a ruby program, I get the correct result.
The documentation for the JSON module indicates that the parse method will "...convert your string into a hash." See http://www.ruby-doc.org/stdlib-2.0.0/libdoc/json/rdoc/JSON.html#module-JSON-label-Parsing+JSON.
Try calling just map on your hash instead of calling map!:
vars = arr.map { |element| element.gsub(/.{3}$/, '' )}
The difference is that map will return a new array with the results of running your block once for every element in the Hash. Also, map is defined in the Enumerable module, which is included by Hash, but map! is not defined in Enumerable. See http://www.ruby-doc.org/core-2.0.0/Enumerable.html#method-i-map.
Related
I am trying to collect elements from an array like below
#arr.collect(&:title)
But sometimes the #arr can have some values and it throws undefined method error. So using try as below.
So how can i handle it with try method?
You can use the way below:
#arr.collect {|e| e.respond_to?(:title) ? e.title : nil }
Or if your Ruby version > 2.3.0, safe navigation operator can be used instead of Rails try:
#arr.collect { |e| e&.title }
I want to merge a hash with default parameters and the actual parameters given in a request. When I call this seemingly innocent script:
#!/usr/bin/env ruby
require 'sinatra'
get '/' do
defaults = { 'p1' => 'default1', 'p2' => 'default2' }
# params = request.params
params = defaults.merge(params)
params
end
with curl http://localhost:4567?p0=request then it crashes with
Listening on localhost:4567, CTRL+C to stop
2016-06-17 11:10:34 - TypeError - no implicit conversion of nil into Hash:
sinatrabug:8:in `merge'
sinatrabug:8:in `block in <main>'
When I access the Rack request.params directly it works. I looked into the Sinatra sources but I couldn't figure it out.
So I have a solution for my actual problem. But I don't know why it works.
My question is: Why can I assign param to a parameter, why is the class Hash but in defaults.merge params it throws an exception?
Any idea?
This is caused by the way Ruby handles local variables and setter methods (i.e. methods that end in =) with the same name. When Ruby reaches the line
params = defaults.merge(params)
it assumes you want to create a new local variable named params, rather than use the method. The initial value of this variable will be nil, and this is the value that the merge method sees.
If you want to refer to the method, you need to refer to it as self.params=. This is for any object that has such a method, not just Sinatra.
A better solution, to avoid this confusion altogether, might be to use a different name. Something like:
get '/' do
defaults = { 'p1' => 'default1', 'p2' => 'default2' }
normalized_params = defaults.merge(params)
normalized_params.inspect
end
Your code is throwing an error because params is nil when you make this call defaults.merge(params). I assume you are trying to merge defaults with request.params, which should contain the parameters from your GET.
Change this line
params = defaults.merge(params)
to this
params = defaults.merge(request.params)
I found this in rack gem
http://www.rubydoc.info/gems/rack/Rack/Request#params-instance_method
It seems you can retrieve GET and POST data by params method but you can't write in it. You have to use update_param and delete_param instead.
I have a class like this:
<div class="qa-share-message ng-isolate-scope ng-valid ta-root
ng-dirty focussed" ng-model="message" text-angular="">
I want to type in this field. i have tried this:
driver.find_elements(:class, "qa-share-message").send_keys("This is a test message")
After running the code it shows error:
undefined method `send_keys' for [#<Selenium::WebDriver::Element:0x65990040 id="33">]:Array
Is it possible to get element by class?
You obviously got elements by class. Look:
undefined method `send_keys' for [# Selenium::WebDriver::Element:0x65990040 id="33"]:Array
the error above clearly says: the call to find_elements succeeded and returned an Array instance, containing Elements. Everything you now need is to either send_keys to each found element:
driver.find_elements(:class, "qa-share-message").each do |e|
e.send_keys("This is a test message")
end
or to send it to one of them, e.g. to the very first one:
driver.find_elements(:class, "qa-share-message")
.first
.send_keys("This is a test message")
How can I access Twitter::Cursor hash values returned by the Twitter API?
I am following the Jumpstartlab Microblogger tutorial for using the Twitter gem via the jumpstart_auth gem.
I am on iteration 4 step 1. I can return a friends object with the following code:
def friends_last_tweets
friends = client.friends
puts friends
end
=> Twitter::Cursor:0x00000104051928
However, the example account, 'client' in this case, has two 'friends' not just one so why does it only return one object? I thought maybe that object is the array or arrays with all of the friends accordingly in hash values within, thus use [] to access, but this returns "undefined method for Twitter::Cursor". I run each on the Twitter::Cursor object and it returns two fixnums:
def friends_last_tweets
friends = client.friends
friends.each { |f| puts f }
end
=> 18908095
108528349
So surely these numbers must represent each 'friend object' within the Twitter::Cursor object me thinks. I need to access the key/value pairs within that object, yet my attempted hash accessing results in undefined method or variable.
In case it's version issue related, I'm using Twitter5.11.0 and Jumpstart_auth 0.6.0.
those answers didn't helped me to get the last message (maybe the API changed in the meantime), that's how I finally did it:
def everyones_last_tweet
puts "\n\n here are the latest tweets of your friends:"
friends = #client.friends.collect { |f| #client.user(f) }
friends.each do |friend|
puts "\n\n#{friend.screen_name} wrote: \n\t #{friend.status.text}"
end
return ""
end
I'm not happy with that return string though
Access the 'friends' object in the same way you accessed the 'followers' object earlier in the tutorial in order to get a list of your followers' screen names.
To get an array of followers' screen names:
screen_names = #client.followers.collect {|f| #client.user(f).screen_name }
To get an array of friends' screen names:
screen_names = #client.friends.collect {|f| #client.user(f).screen_name }
To get the last tweet of a friend, you can use the object_id's you posted above, as:
last_tweet = #client.user(object_id).status.tweet
I hope this helps. I was caught on this issue for a while too.
I am trying 'mongo-ruby-driver' for some project. It's working fine except when I call to_json on mongo object. It gives well formed json but it's not converting BSON::Code into readable value i resulting JSON.
Instead of showing code text, it show something like
#<BSON::Code:0x00000100af6fa8>
Did anyone tried it. Any help id highly appreciated.
UPDATE
here is some code snippet:
#records is variable that contains Array of MongoDB documents in hash.
#records.to_json
When I call to_json on it it gives everything as expected. except for the key that contain BSON::Code (means javascript code). for example consider following doc:
{
"_id" : "contains",
"value" : function( obj, target ) { return obj.indexOf(target) != -1; };
}
Querying same doc from ruby gives output like:
{
"_id"=>"contains",
"value"=><BSON::Code:2160165280 #data="function( obj, target ) { return obj.indexOf(target) != -1; };" #scope="{}">
}
and calling to_json on this gives following:
{"_id":"contains","value":"#<BSON::Code:0x00000100b54658>"}
this is what the problem is. Instead of getting actual code for 'value' key I am getting ruby object as string.
Calling code method on BSON::Code we can get it converted into code. But for that I need to loop mongo docs, check values for each key, calling code on it if it is an object of BSON::Code and then assigning it back to key. And at last we can call to_json on it. But I dont want this much overhead. I need to_json itself should take care of it.
The serializer that is iterating over the attributes of the objects in the array is probably calling the to_s method which would cause the output you are seeing.
You can either monkey patch the BSON::Code class to include a to_s method which calls inspect (the method that produces the output you want) or modify the serializer to detect when it encounters a BSON::Code instance and call inspect on it rather than to_s.
The code to mokey patch the BSON::Code class would look like this:
module BSON
class Code
def to_s
inspect
end
end
end
This would have the same behavior as inspect. If you just wanted the code you could monkey patch this in:
module BSON
class Code
def to_s
#code
end
end
end
I might make this the default behavior for to_s in the driver but for now just include that in your code and it should work like a champ.
Which Mongo object, do you mean the module? If you could, please post the code and what you are trying to do.
The only to_json I see in the driver is BSON::ObjectId#to_json which (from the docs) is described as a method that does the following:
Convert to MongoDB extended JSON format. Since JSON includes type information, but lacks an ObjectId type, this JSON format encodes the type using an $oid key.
I get the same results when I use it:
1.9.3-p0 :001 > require 'mongo'
=> true
1.9.3-p0 :002 > BSON::ObjectId
=> BSON::ObjectId
1.9.3-p0 :003 > BSON::ObjectId.new()
=> BSON::ObjectId('4f17350eadd361e91d000001')
1.9.3-p0 :004 > BSON::ObjectId.new().to_json
=> "{\"$oid\": \"4f173512add361e91d000002\"}"
BSON ( http://bsonspec.org/ ) is a binary representation of JSON ( http://www.json.org/ ) . JSON is not meant to be used to describe functions, as it is meant to be portable. Functions in this manner are not portable to other systems. So there is no way to serialize it. There is some hacks defined here that may get you what you need, but ultimately, BSON/JSON may be a weird tool for the job if your trying to serialize functions.