Tutorial by Examples: i

Type Discovery

By default Code First includes in model Types defined as a DbSet property in context class. Reference types included in entity types even if they are defined in different assembly. Derived classes even if only the base class is defined as DbSet property Here is an example, that we are only...

Entity Framework • Code First Conventions

Filtering hashes

select returns a new hash with key-value pairs for which the block evaluates to true. { :a => 1, :b => 2, :c => 3 }.select { |k, v| k != :a && v.even? } # => { :b => 2 } When you will not need the key or value in a filter block, the convention is to use an _ in that place:...

Ruby Language • Hashes

Set Operations on Hashes

Intersection of Hashes To get the intersection of two hashes, return the shared keys the values of which are equal: hash1 = { :a => 1, :b => 2 } hash2 = { :b => 2, :c => 3 } hash1.select { |k, v| (hash2.include?(k) && hash2[k] == v) } # => { :b => 2 } Union (...

Ruby Language • Hashes

Compile and sign schema

Cleaning and compiling code for iPhone, on project MyProject for schema Qa: xcrun xcodebuild clean \ -workspace "MyProject.xcworkspace" \ -scheme "YourScheme" \ -sdk iphoneos \ -configuration Debug \ archive \ -archivePath builds/MyProject.xcarchive...

Xcode • Command Line Tools

Memory management rules when using manual reference counting.

These rules apply only if you use manual reference counting! You own any object you create By calling a method whose name begins with alloc, new, copy or mutableCopy. For example: NSObject *object1 = [[NSObject alloc] init]; NSObject *object2 = [NSObject new]; NSObject *object3 = [object2 ...

Objective-C Language • Memory Management

One View, Multiple Forms

Here is a quick example of using multiple forms in one Django view. from django.contrib import messages from django.views.generic import TemplateView from .forms import AddPostForm, AddCommentForm from .models import Comment class AddCommentView(TemplateView): post_form_class = AddPo...

Django • Class based views

Timed loop

package main import( "fmt" "time" ) func main() { for _ = range time.Tick(time.Second * 3) { fmt.Println("Ticking every 3 seconds") } }

Go • Loops

Install packages

To install a new package, e.g. aeson: cabal install aeson

Haskell Language • Cabal

Working with sandboxes

A Haskell project can either use the system wide packages or use a sandbox. A sandbox is an isolated package database and can prevent dependency conflicts, e. g. if multiple Haskell projects use different versions of a package. To initialize a sandbox for a Haskell package go to its directory and r...

Haskell Language • Cabal

Managing Open Split Windows (Keyboard Shortcuts)

After you have opened a split window in vim (as demonstrated by many examples under this tag) then you will likely want to control windows quickly. Here is how to control split windows using keyboard shortcuts. Move to split Above/Below: Ctrl + w and k Ctrl + w and j Move to split Left/Right...

vim • Split windows

Window Object Properties

The Window Object contains the following properties. PropertyDescriptionwindow.closedWhether the window has been closedwindow.lengthNumber of <iframe> elements in windowwindow.nameGets or sets the name of the windowwindow.innerHeightHeight of windowwindow.innerWidthWidth of windowwindow.scree...

JavaScript • BOM (Browser Object Model)

Sending HTML Email Using mail()

<?php $to = '[email protected]'; $subject = 'Sending an HTML email using mail() in PHP'; $message = '<html><body>This paragraph is bold.This text is italic.</body></html>'; $headers =...

PHP • Sending Email

Obtain class that satisfies generic parameter at runtime

Many unbound generic parameters, like those used in a static method, cannot be recovered at runtime (see Other Threads on Erasure). However there is a common strategy employed for accessing the type satisfying a generic parameter on a class at runtime. This allows for generic code that depends on ac...

Java Language • Generics

Denying access from IPs to files/directories

# Deny access to a directory from the IP 255.0.0.0 <Directory /path/to/directory> order allow,deny deny from 255.0.0.0 allow from all </Directory> # Deny access to a file from the IP 255.0.0.0 <FilesMatch "^\.ht"> order allow,deny deny fro...

Hypertext Access file • Denying Access

Easy way: python-social-auth

python-social-auth is a framework that simplifies the social authentication and authorization mechanism. It contains many social backends (Facebook, Twitter, Github, LinkedIn, etc.) INSTALL First we need to install the python-social-auth package with pip install python-social-auth or download ...

Django • Django and Social Networks

Installation or Setup

Synopsis A fully functional demo of Firebase v3 Web authentication viewable here. Sign in with Facebook, Github, Google, Twitter, password based, and anonymous accounts. The code, available on Github, is easy to read and follow and is well documented. The focus is on the fully functional authent...

firebase-authentication • Getting started with firebase-authentication

Advanced Insertion Commands and Shortcuts

Here is a quick reference for advanced insertion, formatting, and filtering commands/shortcuts. Command/ShortcutResultg + ? + mPerform rot13 encoding, on movement mn + ctrl + a+n to number under cursorn + ctrl + x-n to number under cursorg + q+ mFormat lines of movement m to fixed width:rce wCenter...

vim • Inserting text

Finding information about a crash

When your app crashes, Xcode will enter the debugger and show you more information about the crash: The most important parts are: The red arrow The red arrow displays which line of code crashed & why it crashed. The debugger console Many crashes log more information to the debugger consol...

iOS • Debugging Crashes

Debugging SIGABRT and EXC_BAD_INSTRUCTION crashes

A SIGABRT or an EXC_BAD_INSTRUCTION usually means the app crashed itself intentionally because some check failed. These should log a message to the debugger console with more information; check there for more information. Many SIGABRTs are caused by uncaught Objective-C exceptions. There are a lo...

iOS • Debugging Crashes

Debugging EXC_BAD_ACCESS

EXC_BAD_ACCESS means the process tried to access memory in an invalid way, like dereferencing a NULL pointer or writing to read-only memory. This is the hardest kind of crash to debug, because it usually does not have an error message, and some crashes can be very difficult to reproduce and/or occu...

iOS • Debugging Crashes