Tutorial by Examples: f

This query returns all cones with a chocolate scoop and a vanilla scoop. VANILLA, CHOCOLATE, MINT, STRAWBERRY = 1, 2, 3, 4 # constants for flavors choco_vanilla_cones = IceCream.objects.filter(scoops__contains=[CHOCOLATE, VANILLA]) Don't forget to import the IceCream model from your models.py ...

You can nest ArrayFields by passing another ArrayField as it's base_field. from django.db import models, IntegerField from django.contrib.postgres.fields import ArrayField class SudokuBoard(models.Model): numbers = ArrayField( ArrayField( models.IntegerField(), ...

This query returns all cones with either a mint scoop or a vanilla scoop. minty_vanilla_cones = IceCream.objects.filter(scoops__contained_by=[MINT, VANILLA])

In order to define a Set of your own type you need to conform your type to Hashable struct Starship: Hashable { let name: String var hashValue: Int { return name.hashValue } } func ==(left:Starship, right: Starship) -> Bool { return left.name == right.name } Now you can cr...

Create a Loader object: var loader:Loader = new Loader(); //import Add listeners on the loader. Standard ones are complete and io/security errors loader.contentLoaderInfo.addEventListener(Event.COMPLETE, loadComplete); //when the loader is done loading, call this function loader.co...

A predefined macro is a macro that is already understood by the C pre processor without the program needing to define it. Examples include Mandatory Pre-Defined Macros __FILE__, which gives the file name of the current source file (a string literal), __LINE__ for the current line number (an int...

To generate an XML documentation file from documentation comments in the code, use the /doc option with the csc.exe C# compiler. In Visual Studio 2013/2015, In Project -> Properties -> Build -> Output, check the XML documentation file checkbox: When you build the project, an XML file wi...

php artisan route:list --method=GET --method=POST This will include all routes that accept GET and POST methods simultaneously.

Horizontally vim -o file1.txt file2.txt Vertically vim -O file1.txt file2.txt You may optionally specify the number of splits to open. The following example opens two horizontal splits and loads file3.txt in a buffer: vim -o2 file1.txt file2.txt file3.txt

So, you make first a .war file let's say a portlet of name <YOUR PLUGIN>.war. You wanna have it running on a glassfish domain under Liferay portal. Steps to success: Navigate to Control Panel -> Plugins Installation on Liferay Hit Install new portlets Hit Configuration Fill in to Dep...

Summary This goal is to reorganize all of your scattered commits into more meaningful commits for easier code reviews. If there are too many layers of changes across too many files at once, it is harder to do a code review. If you can reorganize your chronologically created commits into topical com...

The History Microsoft windows is an operating system available in 137 languages, wrote in C,C++ & Assembly , can be installed on "ARM, IA-32, Itanium, x86-64, DEC Alpha, MIPS, PowerPC" platforms first release was in November 20 ,1985 as windows 1.0 with about 2 billion PC(per...

git log --after '3 days ago' Specific dates work too: git log --after 2016-05-01 As with other commands and flags that accept a date parameter, the allowed date format is as supported by GNU date (highly flexible). An alias to --after is --since. Flags exist for the converse too: --before ...

Itertools "islice" allows you to slice a generator: results = fetch_paged_results() # returns a generator limit = 20 # Only want the first 20 results for data in itertools.islice(results, limit): print(data) Normally you cannot slice a generator: def gen(): n = 0 wh...

Sometimes, you may want something to occur regardless of whatever exception happened, for example, if you have to clean up some resources. The finally block of a try clause will happen regardless of whether any exceptions were raised. resource = allocate_some_expensive_resource() try: do_stu...

In the process of handling an exception, you may want to raise another exception. For example, if you get an IOError while reading from a file, you may want to raise an application-specific error to present to the users of your library, instead. Python 3.x3.0 You can chain exceptions to show how t...

Suggested Install Method Windows: Download and run the binary setup file. Linux(Debian): Run this command in your command line: $ apt-get install python-qt4 pyqt4-dev-tools qt4-designer OS X : Run this command in your command line: $ brew install pyqt Install Manually You can also downloa...

If I wanted to find out the sum of numbers from 1 to n where n is a natural number, I can do 1 + 2 + 3 + 4 + ... + (several hours later) + n. Alternatively, I could write a for loop: n = 0 for i in range (1, n+1): n += i Or I could use a technique known as recursion: def recursion(n): ...

While reading content from a file is already asynchronous using the fs.readFile() method, sometimes we want to get the data in a Stream versus in a simple callback. This allows us to pipe this data to other locations or to process it as it comes in versus all at once at the end. const fs = require(...

App.xaml.cs file (App.xaml file is default, so skipped) using Xamrin.Forms namespace NavigationApp { public partial class App : Application { public static INavigation GlobalNavigation { get; private set; } public App() { InitializeComponent()...