Tutorial by Examples: d

Rust's coherence rule requires that either the trait or the type for which you are implementing the trait must be defined in the same crate as the impl, so it is not possible to implement Serialize and Deserialize for a type in a different crate directly. The newtype pattern and Deref coercion provi...

With functional testing data is often modified. This can cause subsequent runs of the test suite to fail (as the data could have changed from the original state it was in). If you have setup your data source using an ORM or framework that supports migration or seeding (like Doctrine, Propel, Larave...

Because data is sensitive when dealt with between two threads (think concurrent read and concurrent write can conflict with one another, causing race conditions), a set of unique objects were made in order to facilitate the passing of data back and forth between threads. Any truly atomic operation c...

In features/step_definitions/documentation.rb: When /^I go to the "([^"]+)" documentation$/ do |section| path_part = case section when "Documentation" "documentation" else raise "Unknown documentation section: #{section...

PHP is able to parse a number of date formats. If you want to parse a non-standard format, or if you want your code to explicitly state the format to be used, then you can use the static DateTime::createFromFormat method: Object oriented style $format = "Y,m,d"; $time = "2009,2,26&...

Utilizing .Net System.Security.Cryptography.HashAlgorithm namespace to generate the message hash code with the algorithms supported. $example="Nobody expects the Spanish Inquisition." #calculate $hash=[System.Security.Cryptography.HashAlgorithm]::Create("sha256").ComputeHas...

Here is an example of how to define a different action for each Marker's InfoWindow click event. Use a HashMap in which the marker ID is the key, and the value is the corresponding action it should take when the InfoWindow is clicked. Then, use a OnInfoWindowClickListener to handle the event of a ...

Data providers allow creating multiple test inputs to be run within a test. Let's consider a test which verifies that numbers are doubled correctly. To create data provider provide a static method which returns either Object[][] or Iterator<Object[]> (the latter allows for lazy computation of ...

zsh loads configuration from the ~/.zshrc file on startup. If you make changes to that file, you can either restart zsh or run the following command to reload the configuration. . ~/.zshrc You can alias this useful command in your ~/.zshrc like this: alias reload=". ~/.zshrc"

Some Java programmers have a general aversion to throwing or propagating exceptions. This leads to code like the following: public Reader getReader(String pathname) { try { return new BufferedReader(FileReader(pathname)); } catch (IOException ex) { System.out.println(&q...

ExecutorService ExecutorService executor = Executors.newFixedThreadPool(50); It is simple and easy to use. It hides low level details of ThreadPoolExecutor. I prefer this one when number of Callable/Runnable tasks are small in number and piling of tasks in unbounded queue does not increase m...

Entity class @Entity @Table(name = "USER") public class User { @Id @Column(name = "ID") private Long id; @Column(name = "USERNAME") private String username; @ManyToOne @JoinColumn("ORGANIZATION_ID") pr...

If a class is intended to be used polymorphically, with derived instances being stored as base pointers/references, its base class' destructor should be either virtual or protected. In the former case, this will cause object destruction to check the vtable, automatically calling the correct destruc...

PHP 4+ supplies a method, format that converts a DateTime object into a string with a desired format. According to PHP Manual, this is the object oriented function: public string DateTime::format ( string $format ) The function date() takes one parameters - a format, which is a string Format T...

#include <pthread.h> #include <stdio.h> #include <string.h> /* function to be run as a thread always must have the same signature: it has one void* parameter and returns void */ void *threadfunction(void *arg) { printf("Hello, World!\n"); /*printf() is speci...

Consider these two micro-benchmarks: The first benchmark simply creates, starts and joins threads. The thread's Runnable does no work. public class ThreadTest { public static void main(String[] args) throws Exception { while (true) { long start = System.nanoTime(); ...

If you need to store images or videos in the column then we need to change the value as needed by your application max_allowed_packet = 10M M is Mb, G in Gb, K in Kb

Starting with a binary image, bwImg, which contains a number of connected objects. >> bwImg = imread('blobs.png'); >> figure, imshow(bwImg), title('Binary Image') To measure properties (e.g., area, centroid, etc) of every object in the image, use regionprops: >> stats = reg...

By default, Import-CSV imports all values as strings, so to get DateTime- and integer-objects, we need to cast or parse them. Using Foreach-Object: > $listOfRows = Import-Csv .\example.csv > $listOfRows | ForEach-Object { #Cast properties $_.DateTime = [datetime]$_.DateTime $...

get_defined_vars() returns an array with all the names and values of the variables defined in the scope in which the function is called. If you want to print data you can use standard functions for outputting human-readable data, like print_r or var_dump. var_dump(get_defined_vars()); Note: This...