Tutorial by Examples: g

IdlingResource

The power of idling resources lies in not having to wait for some app's processing (networking, calculations, animations, etc.) to finish with sleep(), which brings flakiness and/or prolongs the tests run. The official documentation can be found here. Implementation There are three things that you...

Android • Writing UI tests - Android

Flattening Arrays

2 Dimensional arrays 6 In ES6, we can flatten the array by the spread operator ...: function flattenES6(arr) { return [].concat(...arr); } var arrL1 = [1, 2, [3, 4]]; console.log(flattenES6(arrL1)); // [1, 2, 3, 4] 5 In ES5, we can acheive that by .apply(): function flatten(arr) { ...

JavaScript • Arrays

Simple Boilerplate : spinning cube and orbit controls with damping

This is the basic HTML file that can be used as a boilerplate when starting a project. This boilerplate uses orbit controls with damping (camera that can move around an object with deceleration effect) and creates a spinning cube. <!DOCTYPE html> <html> <head> <t...

three.js • Getting started with three.js

Draw a display object with any coordinates of registration point

public function drawDisplayObjectUsingBounds(source:DisplayObject):BitmapData { var bitmapData:BitmapData;//declare a BitmapData var bounds:Rectangle = source.getBounds(source);//get the source object actual size //round bounds to integer pixel values (to aviod 1px str...

ActionScript 3 • Drawing Bitmaps

Undefined reference errors when linking

One of the most common errors in compilation happens during the linking stage. The error looks similar to this: $ gcc undefined_reference.c /tmp/ccoXhwF0.o: In function `main': undefined_reference.c:(.text+0x15): undefined reference to `foo' collect2: error: ld returned 1 exit status $ So l...

C Language • Common pitfalls

Use the Len function to determine the number of characters in a string

Const baseString As String = "Hello World" Dim charLength As Long charLength = Len(baseString) 'charlength = 11

VBA • Measuring the length of strings

Use the LenB function to determine the number of bytes in a string

Const baseString As String = "Hello World" Dim byteLength As Long byteLength = LenB(baseString) 'byteLength = 22

VBA • Measuring the length of strings

Prefer `If Len(myString) = 0 Then` over `If myString = "" Then`

When checking if a string is zero-length, it is better practice, and more efficient, to inspect the length of the string rather than comparing the string to an empty string. Const myString As String = vbNullString 'Prefer this method when checking if myString is a zero-length string If Len(mySt...

VBA • Measuring the length of strings

Encapsulating API requests

It may be a good idea to encapsulate the HTTP handling logic in its own class. The following class exposes a method for getting Posts. It calls the http.get() method and calls .map on the returned Observable to convert the Response object to a Post object. import {Injectable} from "@angular/co...

Angular 2 • Angular RXJS Subjects and Observables with API requests

Making a connection to a data source

The first step in accessing a data source via ADO is creating an ADO Connection object. This is typically done using a connection string to specify the data source parameters, although it is also possible to open a DSN connection by passing the DSN, user ID, and password to the .Open method. Note t...

VBA • Working with ADO

Retrieving records with a query

Queries can be performed in two ways, both of which return an ADO Recordset object which is a collection of returned rows. Note that both of the examples below use the OpenDatabaseConnection function from the Making a connection to a data source example for the purpose of brevity. Remember that the...

VBA • Working with ADO

Executing non-scalar functions

ADO connections can be used to perform pretty much any database function that the provider supports via SQL. In this case it isn't always necessary to use the Recordset returned by the Execute function, although it can be useful for obtaining key assignments after INSERT statements with @@Identity o...

VBA • Working with ADO

Creating parameterized commands

Any time SQL executed through an ADO connection needs to contain user input, it is considered best practice to parameterize it in order to minimize the chance of SQL injection. This method is also more readable than long concatenations and facilitates more robust and maintainable code (i.e. by using...

VBA • Working with ADO

Scraping Data to build N-gram Word Clouds

The following example utilizes the tm text mining package to scrape and mine text data from the web to build word clouds with symbolic shading and ordering. require(RWeka) require(tau) require(tm) require(tm.plugin.webmining) require(wordcloud) # Scrape Google Finance -----------------------...

R Language • Text mining

Concatenate strings using the & operator

Const string1 As String = "foo" Const string2 As String = "bar" Const string3 As String = "fizz" Dim concatenatedString As String 'Concatenate two strings concatenatedString = string1 & string2 'concatenatedString = "foobar" 'Concatenate three s...

VBA • Concatenating strings

Concatenate an array of strings using the Join function

'Declare and assign a string array Dim widgetNames(2) As String widgetNames(0) = "foo" widgetNames(1) = "bar" widgetNames(2) = "fizz" 'Concatenate with Join and separate each element with a 3-character string concatenatedString = VBA.Strings.Join(widgetNames, &q...

VBA • Concatenating strings

Integer and String identity

Python uses internal caching for a range of integers to reduce unnecessary overhead from their repeated creation. In effect, this can lead to confusing behavior when comparing integer identities: >>> -8 is (-7 - 1) False >>> -3 is (-2 - 1) True and, using another example: ...

Python Language • Common Pitfalls

Use the String function to assign a string with n repeated characters

Dim lineOfHyphens As String 'Assign a string with 80 repeated hyphens lineOfHyphens = String$(80, "-")

VBA • Assigning strings with repeated characters

Use the String and Space functions to assign an n-character string

Dim stringOfSpaces As String 'Assign a string with 255 repeated spaces using Space$ stringOfSpaces = Space$(255) 'Assign a string with 255 repeated spaces using String$ stringOfSpaces = String$(255, " ")

VBA • Assigning strings with repeated characters

Using Java 8 functional interfaces to implement the Strategy pattern

The purpose of this example is to show how we can realize the Strategy pattern using Java 8 functional interfaces. We will start with a simple use case codes in classic Java, and then recode it in the Java 8 way. The example problem we using is a family of algorithms (strategies) that describe dif...

Design patterns • Strategy Pattern