Tutorial by Examples: g

Graph Theory is the study of graphs, which are mathematical structures used to model pairwise relations between objects. Did you know, almost all the problems of planet Earth can be converted into problems of Roads and Cities, and solved? Graph Theory was invented many years ago, even before the in...

I common problem encounter when scrapping a web is how to enter a userid and password to log into a web site. In this example which I created to track my answers posted here to stack overflow. The overall flow is to login, go to a web page collect information, add it a dataframe and then move to t...

Attributes can be useful for denoting metadata on enums. Getting the value of this can be slow, so it is important to cache results. private static Dictionary<object, object> attributeCache = new Dictionary<object, object>(); public static T GetAttribute<T, V>(this V va...

In some cases you may want to change which notification you use based on a tag in the Alert keys. You can do this using the Lookup feature. Note: Lookup only works if you are using OpenTSDB and sending data to the Bosun to be indexed. For other backends or non-indexed data you have to use lookupSeri...

Xcode 8 will automatically recognize any images you’ve got in an Asset Catalog and offer them up as a suggestion inside of a UIImage initializer. So you could basically declare a new variable and then add an asset name that you have added to your asset catalog. For example let img = dog. img does n...

Small, simple csv files can be built using just a text editor, because a CSV file is simply text. If you have spreadsheet software available these are usually an easy way to open and save CSV files. Reading and writing them, or otherwise processing their contents is done more efficiently using the ...

To enable Code First Migrations in entity framework, use the command Enable-Migrations on the Package Manager Console. You need to have a valid DbContext implementation containing your database objects managed by EF. In this example the database context will contain to objects BlogPost and Auth...

Weighted Job Scheduling Algorithm can also be denoted as Weighted Activity Selection Algorithm. The problem is, given certain jobs with their start time and end time, and a profit you make when you finish the job, what is the maximum profit you can make given no two jobs can be executed in parallel...

To store a graph, two methods are common: Adjacency Matrix Adjacency List An adjacency matrix is a square matrix used to represent a finite graph. The elements of the matrix indicate whether pairs of vertices are adjacent or not in the graph. Adjacent means 'next to or adjoining something el...

The Assignment Operator is when you replace the data with an already existing(previously initialized) object with some other object's data. Lets take this as an example: // Assignment Operator #include <iostream> #include <string> using std::cout; using std::endl; class Foo { ...

Ok we have briefly looked over what the copy constructor and assignment constructor are above and gave examples of each now let's see both of them in the same code. This code will be similar as above two. Let's take this : // Copy vs Assignment Constructor #include <iostream> #include <s...

After you've enabled migrations (please refer to this example) you are now able to create your first migration containing an initial creation of all database tables, indexes and connections. A migration can be created by using the command Add-Migration <migration-name> This command will c...

Here's a quick GIF to make the process as easy as it can be. Labels can be applied to issues and pull requests to signify priority, category, or any other information that you find useful. On GitHub, navigate to the main page of the repository. Under your repository name, click Issues or ...

There are several ways to implement a plugin system for a Java application. One of the simplest is to use URLClassLoader. The following example will involve a bit of JavaFX code. Suppose we have a module of a main application. This module is supposed to load plugins in form of Jars from 'plugins' f...

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GO TO label GO TO label-1 label-2 label-3 DEPENDING ON identifier-1 GO TO label OF section GO. The last line example indicates that an ALTER statement is in play, and another part of the code will specify which actual label is the target of the jump.

Given Example class extending BaseExample class with some properties: open class BaseExample(val baseField: String) class Example(val field1: String, val field2: Int, baseField: String): BaseExample(baseField) { val field3: String get() = "Property without backing ...

Consider the dataframes left and right left = pd.DataFrame([['a', 1], ['b', 2]], list('XY'), list('AB')) left A B X a 1 Y b 2 right = pd.DataFrame([['a', 3], ['b', 4]], list('XY'), list('AC')) right A C X a 3 Y b 4 join Think of join as wanting to combine to dat...

The onTouchEvents() for nested view groups can be managed by the boolean onInterceptTouchEvent. The default value for the OnInterceptTouchEvent is false. The parent's onTouchEvent is received before the child's. If the OnInterceptTouchEvent returns false, it sends the motion event down the cha...

type Dog = Dog String dogName1 dog = case dog of Dog name -> name dogName2 (Dog name) -> name dogName1 and dogName2 are equivalent. Note that this only works for ADTs that have a single constructor. type alias Pet = { name: String , weight: Float ...