Tutorial by Examples

Pygame will register all events from the user into an event queue which can be received with the code pygame.event.get(). Every element in this queue is an Event object and they'll all have the attribute type, which is an integer representing what kind of event it is. In the pygame module there are ...

It's possible to call functions from the pygame.key and pygame.mouse module to receive the state of the key and mouse. However, it's not the recommended way to process events in pygame since there are some flaws with it: You'll receive the states when the function is called, which means you mig...

The General Query Log contains a listing of general information from client connects, disconnects, and queries. It is invaluable for debugging, yet it poses as a hindrance to performance (citation?). An example view of a General Query Log is seen below: To determine if the General Log is current...

To determine the version of Azure PowerShell that you have installed, run the following: Get-Module -ListAvailable -Name Azure -Refresh This command returns the installed version even when you haven't loaded the Azure PowerShell module in your current PowerShell session.

Azure Cmdlets let you perform some of the same actions on Azure assets through PowerShell that you would using C# code or the Azure portal. For example, these steps let you download the contents of an Azure blob into a local directory: New-Item -Path .\myblob -ItemType Directory $context = New-Az...

A relation(or relation schema) in a given database is in first normal form, if the domain of all attributes of that relation is atomic. A domain is atomic if all the elements of that domain are considered to indivisible units. Suppose a relation employee, has attribute name, then the relation is not...

To normalize the database in the second form, there must not be any partial dependency of any column on primary key. Let's consider the following example: idnamedobsubject1Mark1-1-1981Physics2Jack2-2-1982Math2Jack2-2-1982Biology3John3-3-1983Math This table is considered to have a composite primar...

If a java library contains interfaces that should be implemented by the user (e.g. click listeners like View.IOnClickListener or callbacks), the implementing class has to inherit -- directly or indirectly -- from Java.Lang.Object or Java.Lang.Throwable. This is a common error, because the packaging ...

In the 32-bit world, the general-purpose registers fall into three general classes: the 16-bit general-purpose registers, the 32-bit extended general-purpose registers, and the 8-bit register halves. These three classes do not represent three entirely distinct sets of registers at all. The 16-bit...

The REPLACE statement can work with regular expressions directly: DATA(lv_test) = 'The quick brown fox'. REPLACE ALL OCCURRENCES OF REGEX '\wo' IN lv_test WITH 'XX'. The variable lv_test will evaluate to The quick bXXwn XXx.

The FIND statement can work with regular expressions directly: DATA(lv_test) = 'The quick brown fox'. FIND REGEX '..ck' IN lv_test. " sy-subrc == 0 FIND REGEX 'a[sdf]g' IN lv_test. " sy-subrc == 4

For more advanced regex operations it's best to use CL_ABAP_REGEX and its related classes. DATA: lv_test TYPE string, lo_regex TYPE REF TO cl_abap_regex. lv_test = 'The quick brown fox'. CREATE OBJECT lo_regex EXPORTING pattern = 'q(...)\w'. DATA(lo_matcher) = lo_regex->cr...

SQL Server 2008 R2 SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED This is the most permissive isolation level, in that it does not cause any locks at all. It specifies that statements can read all rows, including rows that have been written in transactions but not yet committed (i.e., they are...

Step 1. In your host machine (Windows/Linux/OSX), create an empty dir my_project. Step 2. Create a file named Vagrantfile with this: Vagrant.configure("2") do |config| config.vm.box = "gbarbieru/xenial" #An Ubuntu 16.04 based image config.vm.hostname = "my_project&...

To preload remote images and ensure that the image is only downloaded once: Glide.with(context) .load(yourUrl) .diskCacheStrategy(DiskCacheStrategy.SOURCE) .preload(); Then: Glide.with(context) .load(yourUrl) .diskCacheStrategy(DiskCacheStrategy.SOURCE) // ALL works her...

The first mistake that nearly every single programmer makes is presuming that this code will work as intended: float total = 0; for(float a = 0; a != 2; a += 0.01f) { total += a; } The novice programmer assumes that this will sum up every single number in the range 0, 0.01, 0.02, 0.03, .....

Groovy's safe navigation operator allows to avoid NullPointerExceptions when accessing to methods or attributes on variables that may assume null values. It is equivalent to nullable_var == null ? null : nullable_var.myMethod() def lst = ['foo', 'bar', 'baz'] def f_value = lst.find { it.startsWi...

class User { String name int age } def users = [ new User(name: "Bob", age: 20), new User(name: "Tom", age: 50), new User(name: "Bill", age: 45) ] def null_value = users.find { it.age > 100 } // no over-100 found. Null null_value?.name?....

for numbers, a zero value evaluates to false, non zero to true int i = 0 ... if (i) print "some ${i}" else print "nothing" will print "nothing"

a string (including GStrings) evaluates to true if not null and not empty, false if null or empty def s = '' ... if (s) println 's is not empty' else println 's is empty' will print: 's is empty'