How to find the definition of an existing method? - ruby

I am new to programming and Ruby both. In some existing code, it says something like this:
kid_raising_btn=query("switch marked:'KIDRAISING'",:isOn).first
From this, I understand that a variable kid_raising_btn is defined, which will query and return true or false, then call the method first (but this is confusing).
How can I find what first does?

".first" is kind of convenient method.
Answer for the UI query comes as an array.
So the ".first" represent the first element of the array.
There are few methods like ".count"
Ex:
your Query :
ans = query("button",:accessibilityLabel)
Assume You will get result like this
[
[0] "icon rewards new",
[1] "icon my receipts new",
[2] "icon my account",
[3] "icon order#2x",
[4] "icon check in"
]
if you use ".first" like this
ans2 = query("button",:accessibilityLabel).first
you will get a String with first element as a result instead of an array.
"icon rewards new"
Now you can see you get the first element as the answer

From your description, it sounds like the method chaining here might be contributing to your confusion, so first let's rewrite that line of code like this:
query_response = query("switch marked: 'KIDRAISING'", :isOn)
kid_raising_btn = query_response.first
Now, it's easier to see that the #query method returns an object that has a #first method. You can take a look at this object to see what class it is (query_response.class), and then either look up the appropriate documentation for the class or find the method definition in your codebase. For example, if #query returns an array, you can find the documentation here: http://ruby-doc.org/core-2.0.0/Array.html#method-i-first

Related

Using one variable for multiple items data in descriptive programming

I know that with Descriptive programming you can do something like this:
Browser("StackOverflow").Page("StackOverflow").Link("text:=Go To Next Page ", "html tag:=A").Click
But is it possible to create some kind of string so I can assign more than one data value and pass it as single variable? I've tried many combinations using escape characters and I always get error.
For example in the case above, let's say I have more properties in the Page object, so I'd normally have to do something like this:
Browser("StackOverflow").Page("name:=StackOverflow", "html id:=PageID")...etc...
But I'd like to pass "name:=StackOverflow", "html id:=PageID" as a single variable, so when writing many objects I'd only have to write:
Browser(BrowserString).Page(PageString).WebEdit("name:=asdfgh")
And the first part would remain static, so if the parents' data needs to be modified I'd only have to modify two variables and not all the objects created in all libraries.
Is it possible?
If I was not clear enough please let me know.
Thank you in advance!
I think what you're looking for is UFT's Description object
This allows you finer grained control on the description since in descriptive programming all values are regular expressions but with Description you can turn the regular expression functionality off for a specific property.
Set desc = Description.Create()
desc("html tag").Value = "A"
desc("innertext").Value = "More information..."
desc("innertext").RegularExpression = False
Browser("Example Domain").Navigate "www.example.com"
Browser("Example Domain").Page("Example Domain").WebElement(desc).Click
If you want to represent this with plain string then it's a bit more of a problem, you can write a helper function but I'm not sure I would recommend it.
Function Desc(descString)
Set ret = Description.Create()
values = Split(descString, "::")
For Each value In values
keyVal = Split(value, ":=")
ret(keyVal(0)).Value = keyVal(1)
Next
Set Desc = ret
End Function
' Usage
Browser("StackOverflow").Page("StackOverflow").WebElement(Desc("html tag:=H2::innertext:=some text")).Click
Further reading about descriptive programming.
As an alternative to Motti's excellent answer, you could also Set a variable to match your initial descriptive object and then extend it as required:
Set myPage = Browser("StackOverflow").Page("name:=StackOverflow", "html id:=PageID")
after which you can then use
myPage.WebEdit("name:=asdfgh")
throughout the rest of the code, so long as the myPage object stays in scope...

How to use polymorphism to remove a switch statement which compares strings?

I am new to Ruby, so let me describe the context of my problem first:
I have a json as input which has the following key / value pair:
{
"service": "update"
}
The value has many different values for example: insert,delete etc.
Next there is a method x which handles the different requests:
def x(input)
case input[:service]
services = GenericService.new
when "update"
result = services.service(UpdateService.new,input)
when "insert"
result = services.service(InsertService.new,input)
when "delete"
result = services.service(DeleteService.new,input)
....
....
else
raise "Unknown service"
end
puts JSON.pretty_generate(result)
end
What is bothering me is that I still need to use a switch statement to check the String values (reminds me of 'instance of' ugh..). Is there a cleaner way (not need to use a switch)?
Finally I tried to search for an answer to my question and did not succeed, if however I missed it feel free to comment the related question.
Update: I was thinking to maybe cast the string to the related class name as follows: How do I create a class instance from a string name in ruby? and then call result = services.services(x.constantize.new,input) , then the class names ofcourse needs to match the input of the json.
You can try something like:
def x(input)
service_class_name = "#{input[:service].capitalize}Service"
service_class = Kernel.const_get(service_class_name)
service_class.new(input).process
end
In addition you might want to check if this is a valid Service class name at all.
I don't understand why you want to pass the service to GenericService this seems strange. let the service do it's job.
If you're trying to instatiate a class by it's name you're actually speaking about Reflection rather than Polymorphism.
In Ruby you can achieve this in this way:
byName = Object.const_get('YourClassName')
or if you are in a Rails app
byName= 'YourClassName'.constantize
Hope this helps
Just first thoughts, but you can do:
eval(services.service("#{input[:service].capitalize}Service.new, #{input})") if valid_service? input[:service]
def valid_service?
w%(delete update insert).include? input[:service]
end
As folks will no doubt shout, eval needs to be used with alot of care

Create an object if one is not found

How do I create an object if one is not found? This is the query I was running:
#event_object = #event_entry.event_objects.find_all_by_plantype('dog')
and I was trying this:
#event_object = EventObject.new unless #event_entry.event_objects.find_all_by_plantype('dog')
but that does not seem to work. I know I'm missing something very simple like normal :( Thanks for any help!!! :)
find_all style methods return an array of matching records. That is an empty array if no matching records are found. And an empty is truthy. Which means:
arr = []
if arr
puts 'arr is considered turthy!' # this line will execute
end
Also, the dynamic finder methods (like find_by_whatever) are officially depreacted So you shouldn't be using them.
You probably want something more like:
#event_object = #event_entry.event_objects.where(plantype: 'dog').first || EventObject.new
But you can also configure the event object better, since you obviously want it to belong to #event_entry.
#event_object = #event_entry.event_objects.where(plantype: 'dog').first
#event_object ||= #event_entry.event_objects.build(plantype: dog)
In this last example, we try to find an existing object by getting an array of matching records and asking for the first item. If there are no items, #event_object will be nil.
Then we use the ||= operator that says "assign the value on the right if this is currently set to a falsy value". And nil is falsy. So if it's nil we can build the object form the association it should belong to. And we can preset it's attributes while we are at it.
Why not use built in query methods like find_or_create_by or find_or_initialize_by
#event_object = #event_entry.event_objects.find_or_create_by(plantype:'dog')
This will find an #event_entry.event_object with plantype = 'dog' if one does not exist it will then create one instead.
find_or_initialize_by is probably more what you want as it will leave #event_object in an unsaved state with just the association and plantype set
#event_object = #event_entry.event_objects.find_or_initialize_by(plantype:'dog')
This assumes you are looking for a single event_object as it will return the first one it finds with plantype = 'dog'. If more than 1 event_object can have the plantype ='dog' within the #event_entry scope then this might not be the best solution but it seems to fit with your description.

How do I extract a value from this Ruby hash?

I'm using the Foursquare API, and I want to extract the "id" value from this hash
[{"id"=>"4fe89779e4b09fd3748d3c5a", "name"=>"Hitcrowd", "contact"=>{"phone"=>"8662012805", "formattedPhone"=>"(866) 201-2805", "twitter"=>"hitcrowd"}, "location"=>{"address"=>"1275 Glenlivet Drive", "crossStreet"=>"Route 100", "lat"=>40.59089895083072, "lng"=>-75.6291255071468, "postalCode"=>"18106", "city"=>"Allentown", "state"=>"Pa", "country"=>"United States", "cc"=>"US"}, "categories"=>[{"id"=>"4bf58dd8d48988d125941735", "name"=>"Tech Startup", "pluralName"=>"Tech Startups", "shortName"=>"Tech Startup", "icon"=>"https://foursquare.com/img/categories/shops/technology.png", "parents"=>["Professional & Other Places", "Offices"], "primary"=>true}], "verified"=>true, "stats"=>{"checkinsCount"=>86, "usersCount"=>4, "tipCount"=>0}, "url"=>"http://www.hitcrowd.com", "likes"=>{"count"=>0, "groups"=>[]}, "beenHere"=>{"count"=>0}, "storeId"=>""}]
When I try to extract it by using ['id'], I get this error can't convert Symbol into Integer. How do I extract the value using ruby? Also, how do I do this for multiple hashes extracting the "id" value each time?
Please pardon my inexperience. Thanks!
It's wrapped in an array, that's what the [ and ] mean on the start and end. But it also looks like this array only one object in it, which is the hash you really want.
So assuming you want the first object in this array:
mydata[0]['id'] # or mydata.first['id'] as Factor Mystic suggests
But usually when an API returns an Array there is a reason (it might return many results instead of just one), and naively plucking the first item from it my not be what you want. So be sure you are getting the kind of data you really expect before hard coding this into your application.
For multiple hashes, if you want to do something with the id (run a procedure of some kind) then
resultsArray.each do |person|
id = person["id"] #then do something with the id
end
If you want to just get an array containing the ids then
resultsArray.map{|person| person["id"]}
# ["4fe89779e4b09fd3748d3c5a", "5df890079e4b09fd3748d3c5a"]
To just grab the one item from the array, see Alex Wayne's answer
To get an array of ids, try: resultsArray.map { |result| result["id"] }

ruby block questions loop variables

comics = load_comics( '/comics.txt' )
Popup.make do
h1 "Comics on the Web"
list do
comics.each do |name, url|
link name, url
end
end
end
I am new to ruby. This is a piece of code from a ruby website.
I cant find what 'link' and 'list' keyword in the menu.
can someone explain it a little bit those two keywords, and where is the definition of those two keyword .
I am also confused on how they read the variables name and url, they are reading it by the space at the same line or what?
so if I have
Comics1 link_of_comics_site_1
Comics2 link_of_comics_site_2
Comics3 link_of_comics_site_3
so for the first iteration, name=Comics1, and url =link_of_comics_site_1
Thanks.
That's not just Ruby. That's a template for a webpage using ruby add-on methods for HTML generation.
But presumably, the result of the call to load_comics is a Hash, where the keys are names and the values are URLs. You could make one of those yourself:
my_comics_hash = { "name1" => "url1", "name2" => "url2" }
which you can then iterate over the same way:
my_comics_hash.each do |name, url|
puts "Name #{name} goes with URL #{url}"
end
In your code, it's building up an HTML list inside a popup window, but it's the same idea. The each method iterates over a collection - in this case a Hash - and runs some code on every item in that collection - in this case, each key/value pair. When you call each, you pass it a block of code inside do ... end; that's the code that gets run on each item. The current item is passed to the code block, which declares a variable to hold it inside the pipes right after the word do. Since we're iterating over key/value pairs, we can declare two variables, and the key goes in the first and the value in the second.
In ruby function, parenthesis is optional and the ";" end of statement is also optional. ej
link "click here" , "http://myweb.com"
is equivalent to :
link("click here", "http://myweb.com");
But If you have more than one statement in a line the ";" is a must, ej
link("click here1", "http://myweb.com"); link("click here2", "http://myweb.com");
In your code it could be written in
link(name, url)
or just
link(name, url);
or
link name, url
But it is highly recommended to put parenthesis around function parameters for readability unless you have other reason . The ";" is not common in ruby world .

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