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Let's say we have the following function: (defn nat-num-count [nums] (count (remove neg? nums))) We can write a spec for this function by defining a function spec of the same name: (clojure.spec/fdef nat-num-count :args (s/cat :nums (s/coll-of number?)) :ret integer? ...

Hibernate can use two types of fetch when you are mapping the relationship between two entities: EAGER and LAZY. In general, the EAGER fetch type is not a good idea, because it tells JPA to always fetch the data, even when this data is not necessary. Per example, if you have a Person entity and th...

The following terms describe different ways to case identifiers. Pascal Casing The first letter in the identifier and the first letter of each subsequent concatenated word are capitalized. You can use Pascal case for identifiers of three or more characters. For example: BackColor Camel Casing Th...

Use a signal's connect method to connect a function to a signal. When a signal is sent, each connected function is called with the sender and any named arguments the signal provides. from flask import template_rendered def log_template(sender, template, context, **kwargs): sender.logger.in...

The default Angular router allows navigation to and from any route unconditionally. This is not always the desired behavior. In a scenario where a user may conditionally be allowed to navigate to or from a route, a Route Guard may be used to restrict this behavior. If your scenario fits one of the...

File app.routes Protected routes have canActivate binded to Guard import { provideRouter, Router, RouterConfig, CanActivate } from '@angular/router'; //components import { LoginComponent } from './login/login.component'; import { DashboardComponent } from './dashboard/dashboard.component'; ...

You can use the ** keyword argument unpacking operator to deliver the key-value pairs in a dictionary into a function's arguments. A simplified example from the official documentation: >>> >>> def parrot(voltage, state, action): ... print("This parrot wouldn't", ac...

Consider the following dictionaries: >>> fish = {'name': "Nemo", 'hands': "fins", 'special': "gills"} >>> dog = {'name': "Clifford", 'hands': "paws", 'color': "red"} Python 3.5+ >>> fishdog = {**fish, **dog}...

Equality: value equality x == y (1 == 1.0 # true) value inequality x == y (1 != 1.0 # false) strict equality x === y (1 === 1.0 # false) strict inequality x === y (1 !== 1.0 # true) Comparison: x > y x >= y x < y x <= y If types are compatible, comparison uses natural o...

functions.php: // We add the action twice, once for logged in users and once for non logged in users. add_action( 'wp_ajax_my_action', 'my_action_callback' ); add_action( 'wp_ajax_nopriv_my_action', 'my_action_callback' ); // Enqueue the script on the front end. add_action( 'wp_enqueue_script...

The complex entity complex, parameter :: x = (1., 4.) has real part 1. and complex part 4.. We can access these individual components as real(x) ! The real component aimag(x) ! The complex component x%re ! The real component y%im ! The complex component The x%.. form is new to F...

If IPython (or Jupyter) are installed, the debugger can be invoked using: import ipdb ipdb.set_trace() When reached, the code will exit and print: /home/usr/ook.py(3)<module>() 1 import ipdb 2 ipdb.set_trace() ----> 3 print("Hello world!") ipdb> Clea...

The process.env property returns an object containing the user environment. It returns an object like this one : { TERM: 'xterm-256color', SHELL: '/usr/local/bin/bash', USER: 'maciej', PATH: '~/.bin/:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin', PWD: '/Users/maciej', EDITOR: 'vi...

Backpressure is when in an Observable processing pipeline, some asynchronous stages can't process the values fast enough and need a way to tell the upstream producer to slow down. The classic case of the need for backpressure is when the producer is a hot source: PublishSubject<Integer> sour...

There may be situations where you have setup a pool of MySQL connections, but you have a number of queries you would like to run in sequence: SELECT 1; SELECT 2; You could just run then using pool.query as seen elsewhere, however if you only have one free connection in the pool you must wait un...

Dependencies can also be injected by setters. interface Logger { public function log($message); } class Component { private $logger; private $databaseConnection; public function __construct(DatabaseConnection $databaseConnection) { $this->databaseConnection = $...

The most important application events are: Application_Start - It is raised when the application/website is started. Application_End - It is raised when the application/website is stopped. Similarly, the most used Session events are: Session_Start - It is raised when a user first requests a page...

Common page and control events are: DataBinding - It is raised when a control binds to a data source. Disposed - It is raised when the page or the control is released. Error - It is a page event, occurs when an unhandled exception is thrown. Init - It is raised when the page or the control is in...

spray-json provides an easy way to work with JSON. Using implicit formats, everything happens "behind the scenes": Make the Library Available with SBT To manage spray-json with SBT managed library dependencies: libraryDependencies += "io.spray" %% "spray-json" % &quo...

PHP 5.x5.4 When you build REST API's, you may need to reduce the information of an object to be passed to the client application. For this purpose, this example illustrates how to use the JsonSerialiazble interface. In this example, the class User actually extends a DB model object of a hypotetica...