Tutorial by Examples: g

static and templates folder in the apps may should also contain a folder with the name of app ex. blog this is a convention used to prevent namespace pollution, so we reference the files like /blog/base.html rather than /base.html which provides more clarity about the file we are referencing and pre...

In order for a program to react to a certain signal, other than using default action, custom signal handler can be installed using sigaction. sigaction receives three arguments - signal to act on, pointer to sigaction_t structure which, if not NULL, is describing new behaviour and pointer to sigacti...

A string is a sequence of character literals. To date, strings are supported by all modern programming languages,1 but there is no consensus between language designers on how strings should be classified. As far as programming language design is concerned there are two primary concerns to take into ...

SELECT DATE('2003-12-31 01:02:03'); The output will be: 2003-12-31

Least squares is a standard approach to problems with more equations than unknowns, also known as overdetermined systems. Consider the four equations: x0 + 2 * x1 + x2 = 4 x0 + x1 + 2 * x2 = 3 2 * x0 + x1 + x2 = 5 x0 + x1 + x2 = 4 We can express this as a matrix multiplication A * x = b: A ...

Group Concat is used in MySQL to get concatenated values of expressions with more than one result per column. Meaning, there are many rows to be selected back for one column such as Name(1):Score(*) NameScoreAdamA+AdamA-AdamBAdamC+BillD-JohnA- SELECT Name, GROUP_CONCAT(Score ORDER BY Score desc SE...

Use git revert to revert existing commits, especially when those commits have been pushed to a remote repository. It records some new commits to reverse the effect of some earlier commits, which you can push safely without rewriting history. Don't use git push --force unless you wish to bring down ...

You can rename branch in local repository using this command: git branch -m old_name new_name

You can obtain the url for an existing remote by using the command git remote get-url <name> By default, this will be git remote get-url origin

When you created your own Models in a app, they still need to be registered in order to become available in the admin pages. This is done in the admin submodule. If your app was created using manage.py startapp, an admin.py file should already lay in you app module. Otherwise create it. #myapp/a...

There are several packages that allow the output of data structures in form of HTML or LaTeX tables. They mostly differ in flexibility. Here I use the packages: knitr xtable pander For HTML documents --- title: "Printing Tables" author: "Martin Schmelzer" date: &quot...

C++ thrives on what is known as a Regular type (or at least Pseudo-Regular). A Regular type is a type that can be constructed and assigned-to and assigned-from via copy or move, can be destroyed, and can be compared equal-to. It can also be constructed from no arguments. Finally, it also has supp...

The following example illustrates how to use CullingGroups to get notifications according to the distance reference point. This script has been simplified for brevity and uses several performance heavy methods. using UnityEngine; using System.Linq; public class CullingGroupBehaviour : Mono...

Following script illustrates how to receive events according to visibility to a set camera. This script uses several performance heavy methods for brevity. using UnityEngine; using System.Linq; public class CullingGroupCameraBehaviour : MonoBehaviour { CullingGroup localCullingGroup;...

You can add bounding distances on top of culling point radius. They are in a manner additional trigger conditions outside the culling points' main radius, like "close", "far" or "very far". cullingGroup.SetBoundingDistances(new float[] { 0f, 10f, 100f}); Bounding ...

If everything whas been set up correctly, the following snippet will show a window titled "SFML works!" with a green circle: #include <SFML/Graphics.hpp> int main() { sf::RenderWindow window(sf::VideoMode(200, 200), "SFML works!"); sf::CircleShape shape(100.f...

Matplotlib includes the image module for image manipulation import matplotlib.image as mpimg import matplotlib.pyplot as plt Images are read from file (.png only) with the imread function: img = mpimg.imread('my_image.png') and they are rendered by the imshow function: plt.imshow(img) L...

As a developer, you frequently find yourself dealing with strings that are not created by your own code. These will often be supplied by third party libraries, external systems, or even end users. Validating strings of unclear provenance is considered to be one of the hallmarks of defensive program...

The yield keyword allows lazy-evaluation of the collection. Forcibly loading the whole collection into memory is called eager evaluation. The following code shows this: IEnumerable<int> myMethod() { for(int i=0; i <= 8675309; i++) { yield return i; } } ... // ...

Consider using Extension Methods as Functions which wrap other code, here's a great example that uses both a static method and and extension method to wrap the Try Catch construct. Make your code Bullet Proof... using System; using System.Diagnostics; namespace Samples { /// <summary&g...