Tutorial by Examples: c

Attaching a Method to a Button

To add a method to a button, first create an action method: Objective-C -(void) someButtonAction{ NSLog(@"Button is tapped"); } Swift func someButtonAction() { print("Button is tapped") } Now to add this action method to your button, you have to wri...

iOS • UIButton

Convert a sparse matrix to a dense matrix using SciPy

from scipy.sparse import csr_matrix A = csr_matrix([[1,0,2],[0,3,0]]) >>>A <2x3 sparse matrix of type '<type 'numpy.int64'>' with 3 stored elements in Compressed Sparse Row format> >>> A.todense() matrix([[1, 0, 2], [0, 3, 0]]) >>&g...

scipy • Getting started with scipy

Legend Placed Outside of Plot

Sometimes it is necessary or desirable to place the legend outside the plot. The following code shows how to do it. import matplotlib.pylab as plt fig, ax = plt.subplots(1, 1, figsize=(10,6)) # make the figure with the size 10 x 6 inches fig.suptitle('Example of a Legend Being Placed Outside of...

matplotlib • Legends

EXPLAIN Select query

An Explain infront of a select query shows you how the query will be executed. This way you to see if the query uses an index or if you could optimize your query by adding an index. Example query: explain select * from user join data on user.test = data.fk_user; Example result: id select_type...

SQL • EXPLAIN and DESCRIBE

Constructing Types

The type alias keyword combination gives a new name for a type, but the type keyword in isolation declares a new type. Let's examine one of the most fundamental of these types: Maybe type Maybe a = Just a | Nothing The first thing to note is that the Maybe type is declared with a type ...

Elm Language • Types, Type Variables, and Type Constructors

OnChanges

Fired when one or more of the component or directive properties have been changed. import { Component, OnChanges, Input } from '@angular/core'; @Component({ selector: 'so-onchanges-component', templateUrl: 'onchanges-component.html', styleUrls: ['onchanges-component.'] }) class ...

Angular 2 • Lifecycle Hooks

AfterContentInit

Fire after the initialization of the content of the component or directive has finished. (Right after OnInit) import { Component, AfterContentInit } from '@angular/core'; @Component({ selector: 'so-aftercontentinit-component', templateUrl: 'aftercontentinit-component.html', styl...

Angular 2 • Lifecycle Hooks

AfterContentChecked

Fire after the view has been fully initialized. (Only available for components) import { Component, AfterContentChecked } from '@angular/core'; @Component({ selector: 'so-aftercontentchecked-component', templateUrl: 'aftercontentchecked-component.html', styleUrls: ['aftercontentc...

Angular 2 • Lifecycle Hooks

AfterViewChecked

Fire after the check of the view, of the component, has finished. (Only available for components) import { Component, AfterViewChecked } from '@angular/core'; @Component({ selector: 'so-afterviewchecked-component', templateUrl: 'afterviewchecked-component.html', styleUrls: ['afte...

Angular 2 • Lifecycle Hooks

DoCheck

Allows to listen for changes only on specified properties import { Component, DoCheck, Input } from '@angular/core'; @Component({ selector: 'so-docheck-component', templateUrl: 'docheck-component.html', styleUrls: ['docheck-component.'] }) class DoCheckComponent implements DoChe...

Angular 2 • Lifecycle Hooks

Use Trigger to manage a "Recycle Bin" for deleted items

CREATE TRIGGER BooksDeleteTrigger ON MyBooksDB.Books AFTER DELETE AS INSERT INTO BooksRecycleBin SELECT * FROM deleted; GO

SQL • Triggers

Basic usage of Async/Await

You can start some slow process in parallel and then collect the results when they are done: Public Sub Main() Dim results = Task.WhenAll(SlowCalculation, AnotherSlowCalculation).Result For Each result In results Console.WriteLine(result) Next End Sub Async Functio...

Visual Basic .NET Language • Task-based asynchronous pattern

Link CoreLocation Framework

Import the CoreLocation module in your classes that use CoreLocation functionality. //Swift import CoreLocation //Objective-C #import <CoreLocation/CoreLocation.h>

iOS • Core Location

Request Permission to Use Location Services

Check the app's authorization status with: //Swift let status: CLAuthorizationStatus = CLLocationManager.authorizationStatus() //Objective-C CLAuthorizationStatus status = [CLLocationManager authorizationStatus]; Test the status against the follow constants: //Swift switch status { case ...

iOS • Core Location

In what package should I define my ASDF system?

ASDF provides the package ASDF-USER for developers to define their packages in.

common-lisp • ASDF - Another System Definition Facility

Copy to clipboard from textarea using execCommand("copy")

Example: <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> </head> <body> <textarea id="content"></textarea> <input type="button" id="copy...

JavaScript • execCommand and contenteditable

Character class and common problems faced by beginner

1. Character Class Character class is denoted by []. Content inside a character class is treated as single character separately. e.g. suppose we use [12345] In the example above, it means match 1 or 2 or 3 or 4 or 5 . In simple words, it can be understood as or condition for single characters (...

Regular Expressions • Character classes

Block with

The blockquote element can be used for a (block-level) quote: <blockquote> <p>The answer is 42.</p> </blockquote> Source URL (cite attribute) The cite attribute can be used to reference the URL of the quoted source: <blockquote cite="http://example.com/blog/...

HTML • Marking-up Quotes

Moving scroll when UITextView becomes first responder

Observe the notifications UIKeyboardWillShowNotification and UIKeyboardWillHideNotification, update the scrollView content insets according to keyboard height, then scroll to the focused control. - (void)viewDidLoad { [super viewDidLoad]; // register for keyboard notifications [[...

iOS • UITextField

Setting a cookie

To set a cookie i.e. to create it and schedule for sending to the browser you need to create new \yii\web\Cookie class instance and add it to response cookies collection: $cookie = new Cookie([ 'name' => 'cookie_monster', 'value' => 'Me want cookie!', 'expire' => time() + 86...

yii2 • Cookies