Tutorial by Examples: r

1- Define Your own custom Block typedef void(^myCustomCompletion)(BOOL); 2- Create custom method which takes your custom completion block as a parameter. -(void) customMethodName:(myCustomCompletion) compblock{ //do stuff // check if completion block exist; if we do not check it will ...

Resource loading in Java comprises the following steps: Finding the Class or ClassLoader that will find the resource. Finding the resource. Obtaining the byte stream for the resource. Reading and processing the byte stream. Closing the byte stream. The last three steps are typically accomp...

React components that are pure functions of their props and do not require any internal state can be written as JavaScript functions instead of using the standard class syntax, as: import React from 'react' const HelloWorld = (props) => ( <h1>Hello, {props.name}!</h1> ); ...

The simplest react component without a state and no properties can be written as: import * as React from 'react'; const Greeter = () => <span>Hello, World!</span> That component, however, can't access this.props since typescript can't tell if it is a react component. To access ...

VueJS can be used to easily handle user input as well, and the two way binding using v-model makes it really easy to change data easily. HTML : <script src="https://unpkg.com/vue/dist/vue.js"></script> <div id="app"> {{message}} <input v-model="...

This technique relies on adding thick borders to the link itself to build the button's CTA. Using borders is universally understood by email clients, but limit button appearance solid colors. <table width="100%" border="0" cellspacing="0" cellpadding="0"&g...

This technique uses a combination of border-based and padding-based buttons, styling the link with both padding and at least a solid 1px border. The background color needs to be applied to the instead of the in this instance because Outlook does recognize horizontal padding on the tag (since it's...

This button derives from this example by Email on Acid. It is entirely code-based, so it will display without images downloaded, and the entire button is hoverable + clickable. Additionally, this example also includes spacers to help control how much vertical space appears before and after the butt...

SELECT 1 a, '' b from DUAL; AB1(null)

SELECT 3 * NULL + 5, 'Hello ' || NULL || 'world' from DUAL; 3*NULL+5'HELLO'||NULL||'WORLD'(null)Hello world

SELECT a column_with_null, NVL(a, 'N/A') column_without_null FROM (SELECT NULL a FROM DUAL); COLUMN_WITH_NULLCOLUMN_WITHOUT_NULL(null)N/A NVL is useful to compare two values which can contain NULLs : SELECT CASE WHEN a = b THEN 1 WHEN a <> b THEN 0 else -1 END comparison_without_n...

If the first parameter is NOT NULL, NVL2 will return the second parameter. Otherwise it will return the third one. SELECT NVL2(null, 'Foo', 'Bar'), NVL2(5, 'Foo', 'Bar') FROM DUAL; NVL2(NULL,'FOO','BAR')NVL2(5,'FOO','BAR')BarFoo

SELECT COALESCE(a, b, c, d, 5) FROM (SELECT NULL A, NULL b, NULL c, 4 d FROM DUAL); COALESCE(A,B,C,D,5)4 In some case, using COALESCE with two parameters can be faster than using NVL when the second parameter is not a constant. NVL will always evaluate both parameters. COALESCE will stop a...

A Frame is created like any other controls: <Frame x:Name="contentRoot" Navigated="OnNavigated" Navigating="OnNavigating" /> The navigated/navigating events can then be intercepted to cancel the navigation or show/hide the back button. private...

A function that extends the functionality of the array by creating an object oriented remove function. // Need to restrict the extension to elements that can be compared. // The `Element` is the generics name defined by Array for its item types. // This restriction also gives us access to `index(...

There are some spawning rules in Worlds in Bukkit. They are: Animal Spawning Creature Spawning Amount of the above that can be spawned Animal Spawning Animal spawning can be split into the following categories: Water Animals Land Animals To get the amount of animals that can be...

Detailed instructions on getting c++-cli set up or installed.

MQTT(Message Queue Telemetry Transport) is a Publish-Subscribe based "lightweight" messaging protocol for use on top of the TCP/IP stack. It is quite useful for connections with remote locations where a small code footprint is required and/or network bandwidth is at a premium. Ther...

import cv2 def canny_webcam(): "Live capture frames from webcam and show the canny edge image of the captured frames." cap = cv2.VideoCapture(0) while True: ret, frame = cap.read() # ret gets a boolean value. True if reading is successful (I think). frame ...

An input port can be created in many ways, but usually the method starts with open-input-. String port You can use a string as a port using open-input-string. It will create a port that will be able to read from the string. (define p (open-input-string "(a . (b . (c . ()))) 34")) ...