Tutorial by Examples: accessi

class Vector { double x double y } def points = [ new Vector(x: 10, y: -5), new Vector(x: -17.5, y: 3), new Vector(x: -3.3, y: -1) ] assert points*.x == [10, -17.5, -3.3] Note: The * is optional. We could also write the above statement as in the below line and Groov...

Installing aws cli in Ubuntu / Debian Instance sudo apt-get install -y python-dev python-pip sudo pip install awscli aws --version aws configure Installing aws cli using python Using pip you can install aws cli in windows, OS X and Linux sudo pip install awscli Configuring the AWS Comman...

The password in a credential object is an encrypted [SecureString]. The most straightforward way is to get a [NetworkCredential] which does not store the password encrypted: $credential = Get-Credential $plainPass = $credential.GetNetworkCredential().Password The helper method (.GetNetworkCrede...

Member member/2 has signature member(?Elem, ?List) and denotes true if Elem is a member of List. This predicate can be used to access variables in a list, where different solutions are retrieved through backtracking. Example queries: ?- member(X, [1,2,3]). X = 1 ; X = 2 ; X = 3. ?- member(X...

Using the dataset property The new dataset property allows access (for both reading and writing) to all data attributes data-* on any element. <p>Countries:</p> <ul> <li id="C1" onclick="showDetails(this)" data-id="US" data-dial-code="1&q...

Static server assets must be placed in the private directory. Text files Text files can be accessed by using the Assets.getText(assetPath, [asyncCallback]) method. For example, the following JSON file is named my_text_asset.json and is located in the private directory: { "title": &...

Starting with a three-dimensional list: alist = [[[1,2],[3,4]], [[5,6,7],[8,9,10], [12, 13, 14]]] Accessing items in the list: print(alist[0][0][1]) #2 #Accesses second element in the first list in the first list print(alist[1][1][2]) #10 #Accesses the third element in the second list in...

You might have heard that everything in Python is an object, even literals. This means, for example, 7 is an object as well, which means it has attributes. For example, one of these attributes is the bit_length. It returns the amount of bits needed to represent the value it is called upon. x = 7 ...

They're not easily accessible. If you run the 'meteor bundle' command, you can generate a tar.gz file, and then run your app manually. Doing that, you should be able to access the mongo logs... probably in the .meteor/db directory. If you really need to access mongodb log files, set up a regular mo...

The format of the struct statement is this: struct [structure tag] { member definition; member definition; ... member definition; } [one or more structure variables]; Example: declare the ThreeFloats structure: typedef struct { float x, y, z; } ThreeFloats; @inter...

The first thing you need to do is create a connection to the database using the connect method. After that, you will need a cursor that will operate with that connection. Use the execute method of the cursor to interact with the database, and every once in a while, commit the changes using the comm...

There are two ways to get singleton class of an object singleton_class method. Reopening singleton class of an object and returning self. object.singleton_class singleton_class = class << object self end

Singleton classes share their instance/class variables with their object. class Example @@foo = :example end def Example.foo class_variable_get :@@foo end Example.foo #=> :example class Example def initialize @foo = 1 end def foo @foo end end e = Ex...

If you want to change an attribute of a control such as a textbox or label from another thread than the GUI thread that created the control, you will have to invoke it or else you might get an error message stating: "Cross-thread operation not valid: Control 'control_name' accessed from a th...

Use a mutex to synchronise access to a variable which is accessed from multiple threads: counter = 0 counter_mutex = Mutex.new # Start three parallel threads and increment counter 3.times.map do |index| Thread.new do counter_mutex.synchronize { counter += 1 } end end.each(&:joi...

When executing a Bash script, parameters passed into the script are named in accordance to their position: $1 is the name of the first parameter, $2 is the name of the second parameter, and so on. A missing parameter simply evaluates to an empty string. Checking for the existence of a parameter can...

In most cases, it is illegal to access an object of one type as though it were a different type (disregarding cv-qualifiers). Example: float x = 42; int y = reinterpret_cast<int&>(x); The result is undefined behavior. There are some exceptions to this strict aliasing rule: An obj...

By adding the following extension to array indices can be accessed without knowing if the index is inside bounds. extension Array { subscript (safe index: Int) -> Element? { return indices ~= index ? self[index] : nil } } example: if let thirdValue = array[safe: 2] { ...

You can find description of the driver here. The quick example is: import psycopg2 db_host = 'postgres.server.com' db_port = '5432' db_un = 'user' db_pw = 'password' db_name = 'testdb' conn = psycopg2.connect("dbname={} host={} user={} password={}".format( ...

It is illegal to access a reference to an object that has gone out of scope or been otherwise destroyed. Such a reference is said to be dangling since it no longer refers to a valid object. #include <iostream> int& getX() { int x = 42; return x; } int main() { int& r...