Tutorial by Examples: r

When a method need to accept an "extensible" set of enum values, the programmer can apply polymorphism like on a normal class by creating an interface which will be used anywere where the enums shall be used: public interface ExtensibleEnum { String name(); } This way, any enum t...

2.2 let aString = "This is a test string." // first, reverse the String's characters let reversedCharacters = aString.characters.reverse() // then convert back to a String with the String() initializer let reversedString = String(reversedCharacters) print(reversedString) // &q...

Method 1: Below query will be applicable for SQL Server 2000+ version (Contains 12 columns) SELECT * FROM dbo.sysdatabases Method 2: Below query extract information about databases with more informations (ex: State, Isolation, recovery model etc.) Note: This is a catalog view and will be availa...

Introduction Interfaces are definitions of the public APIs classes must implement to satisfy the interface. They work as "contracts", specifying what a set of subclasses does, but not how they do it. Interface definition is much alike class definition, changing the keyword class to inter...

Adding elements: [1, 2, 3] << 4 # => [1, 2, 3, 4] [1, 2, 3].push(4) # => [1, 2, 3, 4] [1, 2, 3].unshift(4) # => [4, 1, 2, 3] [1, 2, 3] << [4, 5] # => [1, 2, 3, [4, 5]] Removing elements: array = [1, 2, 3, 4] array.pop # => 4 array # => [1, 2, 3] ...

Default behaviour is when the merge resolves as a fast-forward, only update the branch pointer, without creating a merge commit. Use --no-ff to resolve. git merge <branch_name> --no-ff -m "<commit message>"

In Python 2, print is a statement: Python 2.x2.7 print "Hello World" print # print a newline print "No newline", # add trailing comma to remove newline print >>sys.stderr, "Error" # print to stderr print("hello"...

This example shows, how to start intent from browser: <a href="intent://host.com/path#Intent;package=com.sample.test;scheme=yourscheme;end">Start intent</a> This intent will start app with package com.sample.test or will open google play with this package. Also this intent...

Code first allows you to create your entities (classes) without using a GUI designer or a .edmx file. It is named Code first, because you can create your models first and Entity framework will create database according to mappings for you automatically. Or you can also use this approach with existin...

Windows If you have Visual Studio (any version including express and community) installed, F# should already be included. Just choose F# as the language when you create a new project. Or see http://fsharp.org/use/windows/ for more options. OS X Xamarin Studio supports F#. Alternately, you could u...

Even just reading the value of a pointer that was freed (i.e. without trying to dereference the pointer) is undefined behavior(UB), e.g. char *p = malloc(5); free(p); if (p == NULL) /* NOTE: even without dereferencing, this may have UB */ { } Quoting ISO/IEC 9899:2011, section 6.2.4 §2: ...

Functions can take inputs in form of variables that can be used and assigned inside their own scope. The following function takes two numeric values and returns their sum: function addition (argument1, argument2){ return argument1 + argument2; } console.log(addition(2, 3)); // -> 5 ...

x = [5, 5, 1, 3] y = [5, 2, 4, 3] Union (|) contains elements from both arrays, with duplicates removed: x | y => [5, 1, 3, 2, 4] Intersection (&) contains elements which are present both in first and second array: x & y => [5, 3] Difference (-) contains elements which ar...

Stability in sorting means whether a sort algorithm maintains the relative order of the equals keys of the original input in the result output. So a sorting algorithm is said to be stable if two objects with equal keys appear in the same order in sorted output as they appear in the input unsorted a...

If a selection on multiple arguments for a type generic expression is wanted, and all types in question are arithmetic types, an easy way to avoid nested _Generic expressions is to use addition of the parameters in the controlling expression: int max_int(int, int); unsigned max_unsigned(unsigned, ...

Note: Before deciding which Stream to use please have a look at ParallelStream vs Sequential Stream behavior. When you want to perform Stream operations concurrently, you could use either of these ways. List<String> data = Arrays.asList("One", "Two", "Three", &q...

The FOR XML PATH can be used for concatenating values into string. The example below concatenates values into a CSV string: DECLARE @DataSource TABLE ( [rowID] TINYINT ,[FirstName] NVARCHAR(32) ); INSERT INTO @DataSource ([rowID], [FirstName]) VALUES (1, 'Alex') ,(2, 'Peter') ...

Windows PowerShell is included with the Windows Management Framework. Installation and Setup are not required on modern versions of Windows. Updates to PowerShell can be accomplished by installing a newer version of the Windows Management Framework. Other Platforms "Beta" version of P...

Sometimes you want to iterate over a range of dates from a start date to some end date. You can do it using datetime library and timedelta object: import datetime # The size of each step in days day_delta = datetime.timedelta(days=1) start_date = datetime.date.today() end_date = start_date ...

The following examples show two main methods for installing Erlang/OTP on Ubuntu. Method 1 - Pre-built Binary Package Simply run this command and it will download and install the latest stable Erlang release from Erlang Solutions. $ sudo apt-get install erlang Method 2 - Build and Install from...