Tutorial by Examples: le

1) Create a Contract Class A contract class defines constants that help applications work with the content URIs, column names, intent actions, and other features of a content provider. Contract classes are not included automatically with a provider; the provider's developer has to define them and t...

DELETE FROM `myTable` WHERE `someColumn` = 'something' The WHERE clause is optional but without it all rows are deleted.

A common problem is having a collection of items that all need to meet a certain criteria. In the example below we have collected two items for a diet plan and we want to check that the diet doesn't contain any unhealthy food. // First we create a collection $diet = collect([ ['name' => ...

You will often find yourself with a collection of data where you are only interested in parts of the data. In the example below we got a list of participants at an event and we want to provide a the tour guide with a simple list of names. // First we collect the participants $participants = colle...

Often you need to change the way a set of data is structured and manipulate certain values. In the example below we got a collection of books with an attached discount amount. But we much rather have a list of books with a price that's already discounted. $books = [ ['title' => 'The Pragma...

Collections also provide you with an easy way to do simple statistical calculations. $books = [ ['title' => 'The Pragmatic Programmer', 'price' => 20], ['title' => 'Continuous Delivery', 'price' => 30], ['title' => 'The Clean Coder', 'price' => 10], ] $min = col...

Sometimes you will have a grid of subplots, and you want to have a single legend that describes all the lines for each of the subplots as in the following image. In order to do this, you will need to create a global legend for the figure instead of creating a legend at the axes level (which wil...

Not always we have liberty to read from or write to a local system path. For example if R code streaming map-reduce must need to read and write to file connection. There can be other scenarios as well where one is going beyond local system and with advent of cloud and big data, this is becoming incr...

C++11 It's possible to write a generic function (for example min) which accepts various numerical types and arbitrary argument count by template meta-programming. This function declares a min for two arguments and recursively for more. template <typename T1, typename T2> auto min(const T1 &...

Make project (compile modifed and dependent) Windows: Ctrl + F9 OS X / macOS: Cmd + F9 Compile selected file, package or module This is useful to know, as when debugging this shortcut can be used to quickly reload / hotswap classes. Windows: Ctrl + Shift + F9 OS X / macOS: Cmd + Shift + F9 Se...

Basic code completion (the name of any class, method or variable) Windows: Ctrl + Space OS X / macOS: Cmd + Space Smart code completion (filters the list of methods and variables by expected type) Windows: Ctrl + Shift + Space OS X / macOS: Cmd + Shift + Space Overwriting code with a suggestio...

module SomeMixin def foo puts "foo!" end end class Bar include SomeMixin def baz puts "baz!" end end b = Bar.new b.baz # => "baz!" b.foo # => "foo!" # works thanks to the mixin Now Bar is a mix of it...

You can read an a binary file using this piece of code in all recent versions of Java: Java SE 1.4 File file = new File("path_to_the_file"); byte[] data = new byte[(int) file.length()]; DataInputStream stream = new DataInputStream(new FileInputStream(file)); stream.readFully(data); s...

This code compiles: Integer arg = null; int x = arg; But it will crash at runtime with a java.lang.NullPointerException on the second line. The problem is that a primitive int cannot have a null value. This is a minimalistic example, but in practice it often manifests in more sophisticated f...

Simple Single Port RAM with one address for read/write operations. module ram_single #( parameter DATA_WIDTH=8, //width of data bus parameter ADDR_WIDTH=8 //width of addresses buses )( input [(DATA_WIDTH-1):0] data, //data to be written input [(ADDR_WIDTH-1):0] ad...

In Symfony it's possible to define multiple routes for one action. This can be very helpful if you have functions that do the same but have different parameters. class TestController extends Controller { /** * @Route("/test1/{id}", name="test") * @Route("/...

This example uses Parallel.ForEach to calculate the sum of the numbers between 1 and 10000 by using multiple threads. To achieve thread-safety, Interlocked.Add is used to sum the numbers. using System.Threading; int Foo() { int total = 0; var numbers = Enumerable.Range(1, 10000).ToLis...

This example uses Parallel.For to calculate the sum of the numbers between 1 and 10000 by using multiple threads. To achieve thread-safety, Interlocked.Add is used to sum the numbers. using System.Threading; int Foo() { int total = 0; Parallel.For(1, 10001, () => 0, // in...

ctrl + alt + shift + / (cmd + alt + shift + / on MacOS) should show you the following dialog: Clicking on Registry you will get The key you want to enable/disable is editor.skip.copy.and.cut.for.empty.selection Tested on Linux Ubuntu and MacOS.

To switch the value of two variables you can use tuple unpacking. x = True y = False x, y = y, x x # False y # True