Tutorial by Examples: io

To create a human-readable presentation of a model object you need to implement Model.__str__() method (or Model.__unicode__() on python2). This method will be called whenever you call str() on a instance of your model (including, for instance, when the model is used in a template). Here's an exampl...

itertools.combinations will return a generator of the k-combination sequence of a list. In other words: It will return a generator of tuples of all the possible k-wise combinations of the input list. For Example: If you have a list: a = [1,2,3,4,5] b = list(itertools.combinations(a, 2)) print ...

+currentCalendar returns the logical calendar for the current user. NSCalendar *calender = [NSCalendar currentCalendar]; NSLog(@"%@",calender); +autoupdatingCurrentCalendar returns the current logical calendar for the current user. NSCalendar *calender = [NSCalendar autoupdat...

- components:fromDate: Returns a NSDateComponents object containing a given date decomposed into specified components NSCalendar *calender = [NSCalendar autoupdatingCurrentCalendar]; [calender setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]]; NSLog(@"%@",[calender components:NSCale...

This book is known as CLtL2. This is the second edition of the book Common Lisp the Language. It was published in 1990, before the ANSI CL standard was final. It took the original language definition from the first edition (published in 1984) and described all changes in the standardization process...

To start tinkering with Roslyn you will need the following NuGet packages: The C# and VB compilers - Microsoft.Net.Compilers. To install it you can run the following command in the Package Manager Console: nuget install Microsoft.Net.Compilers The Language APIs and Services - Microsoft.Co...

XSD, XML Schema Definition, is a language which describes the structure of XML documents. XSD files can be used to validate an XML file. The process of doing this will depend on what you choose to implement it with. Care should be taken to ensure the validation engine you use is compatible with the ...

On CLiki, a Wiki for Common Lisp and free Common Lisp software, a list of Proposed ANSI Revisions and Clarifications is being maintained. Since the Common Lisp standard has not changed since 1994, users have found several problems with the specification document. These are documented on the CLiki p...

From the official documentation: If you want to get advanced, you can also open up the project file for a specific platform by opening the required XCode or Android Eclipse project in platforms/PLATFORM inside the root of your project. Then, you can build and test from inside the platform-specifi...

Check if a path is a directory or a file The is_dir function returns whether the argument is a directory, while is_file returns whether the argument is a file. Use file_exists to check if it is either. $dir = "/this/is/a/directory"; $file = "/this/is/a/file.txt"; echo is_d...

To make a class a subclass of another class, use parent pragma: package Point; use strict; ... 1; package Point2D; use strict; use parent qw(Point); ... 1; package Point3D; use strict; use parent qw(Point); ... 1; Perl allows for multiple inheritance: package Point2D; use stri...

To get the previous element you can use the .prev() method. <ul> <li>Mark</li> <li class="anna">Anna</li> <li>Paul</li> </ul> If you are standing on the "Anna" element and you want to get the previous element, &q...

To filter a selection you can use the .filter() method. The method is called on a selection and returns a new selection. If the filter matches an element then it is added to the returned selection, otherwise it is ignored. If no element is matched then an empty selection is returned. The HTML Thi...

Until Java 8, two instances of the same annotation could not be applied to a single element. The standard workaround was to use a container annotation holding an array of some other annotation: // Author.java @Retention(RetentionPolicy.RUNTIME) public @interface Author { String value(); } ...

Collections in Java only work for objects. I.e. there is no Map<int, int> in Java. Instead, primitive values need to be boxed into objects, as in Map<Integer, Integer>. Java auto-boxing will enable transparent use of these collections: Map<Integer, Integer> map = new HashMap<&g...

ISO/ANSI SQL: SELECT Id, Col1 FROM TableName ORDER BY Id OFFSET 20 ROWS FETCH NEXT 20 ROWS ONLY; MySQL: SELECT * FROM TableName LIMIT 20, 20; -- offset, limit Oracle; SQL Server: SELECT Id, Col1 FROM (SELECT Id, Col1, row_number() over (order by Id) RowNumbe...

Options have some useful higher-order functions that can be easily understood by viewing options as collections with zero or one items - where None behaves like the empty collection, and Some(x) behaves like a collection with a single item, x. val option: Option[String] = ??? option.map(_.trim) ...

Panels can have sections, sections can have settings, and settings can have controls. Settings are saved in the database, while the controls for particular settings are only used to display their corresponding setting to the user. This code creates a basic section in the panel from above. Inside a...

Add typings to your package.json { ... "typings": "path/file.d.ts" ... } Now when ever that library is imported typescript will load the typings file

Introduction JetBrains PhpStorm is a commercial, cross-platform IDE for PHP. It is built on JetBrains' IntelliJ IDEA platform, which is written in Java. It will thus run on all major operating systems that support Java. Users can extend the IDE by installing plugins created for the IntelliJ Platfo...