Tutorial by Examples: g

Downloading a file using the Dropbox Java library

This uses the Dropbox Java SDK to download a file from the Dropbox API at the remote path /Homework/math/Prime_Numbers.txt to the local file Prime_Numbers.txt: String localPath = "Prime_Numbers.txt"; OutputStream outputStream = new FileOutputStream(localPath); FileMetadata metadata = cl...

Dropbox API • Downloading a file

Using an index for a date and time lookup

Many real-world database tables have many rows with DATETIME OR TIMESTAMP column values spanning a lot of time, including years or even decades. Often it's necessary to use a WHERE clause to retrieve some subset of that timespan. For example, we might want to retrieve rows for the date 1-September-2...

MySQL • Date and Time Operations

Big O

Big O notation provides upper bounds for the growth of functions. Intuitively for f ∊ O(g), f grows at most as fast as g. Formally f ∊ O(g) if and only if there is a positive number C and a positive number ``n such that for all positive numbers m > n we have C⋅g(m) > f(m). Intuition of ...

time-complexity • Landau Notation

Pitfall - Using "Yoda notation" to avoid NullPointerException

A lot of example code posted on StackOverflow includes snippets like this: if ("A".equals(someString)) { // do something } This does "prevent" or "avoid" a possible NullPointerException in the case that someString is null. Furthermore, it is arguable that ...

Java Language • Java Pitfalls - Nulls and NullPointerException

Splitting text strings over multiple lines

- Without quotes: You can just split a long piece of text like this. - With quotes: "[But be careful: if you \"need\" punctuation, put double quotes around it. You can ev\ en split without spaces by using backslashes." - Or single quotes: 'This wor...

yaml • Getting started with yaml

Basic PL/pgSQL Trigger Function

This is a simple trigger function. CREATE OR REPLACE FUNCTION my_simple_trigger_function() RETURNS trigger AS $BODY$ BEGIN -- TG_TABLE_NAME :name of the table that caused the trigger invocation IF (TG_TABLE_NAME = 'users') THEN --TG_OP : operation the trigger was fired IF (TG_O...

postgresql • Triggers and Trigger Functions

_design/example

Design documents contain application logic. Any document in a database that has an _id starting with "_design/" can be used as design document. Usually there is one design document for each application. { "_id": "_design/example", "view": { ...

couchdb • Design Documents

Assignments model in PL/SQL

All programming languages allow us to assign values to variables. Usually, a value is assigned to variable, standing on left side. The prototype of the overall assignment operations in any contemporary programming language looks like this: left_operand assignment_operand right_operand instructions_...

plsql • Assignments model and language

Setting and getting pixel values of a Gray image in C++

// PixelAccessTutorial.cpp : Defines the entry point for the console // Environment: Visual studio 2015, Windows 10 // Assumptions: Opecv is installed configured in the visual studio project // Opencv version: OpenCV 3.1 #include "stdafx.h" #include<opencv2/core/core.hpp> #i...

opencv • Pixel Access

Angular 2 for-loop

For live plnkr click... <!doctype html> <html> <head> <title>ng for loop in angular 2 with ES5.</title> <script type="text/javascript" src="https://code.angularjs.org/2.0.0-alpha.28/angular2.sfx.dev.js"></script> <scr...

Angular 2 • Angular - ForLoop

Selecting by multiple criteria [C#]

It's also possible to use selectors together. This is done by using the OpenQA.Selenium.Support.PageObjects.ByChained object: element = driver.FindElement(new ByChained(By.TagName("input"), By.ClassName("class")); Any number of Bys can be chained and are used as an AND type ...

selenium-webdriver • Locating Web Elements

Canny Algorithm - C++

Below is an usage of canny algorithm in c++. Note that the image is first converted to grayscale image, then Gaussian filter is used to reduce the noise in the image. Then Canny algorithm is used for edge detection. // CannyTutorial.cpp : Defines the entry point for the console application. // En...

opencv • Edge detection

Reading .gz textfile line after line

This class open a .gz file (usual format of compressed log files) and will return a line at each call of .NextLine() There is no memory usage for temporary decompression, very useful for large file. Imports System.IO Class logread_gz Private ptr As FileStream Private UnGZPtr As Compress...

Visual Basic .NET Language • Reading compressed textfile on-the-fly

Working with nested looping

Here is the JSON Structure we are going to use. { "employees": [ { "firstName": "John", "lastName": "Doe", "skills": [ { "name": "javascript", "rating&quo...

knockout.js • Working with knockout foreach binding with JSON

Increment-Decrement operators as arguments in Methods

Though Go supports ++ and -- operators and the behaviour is found to be almost similar to c/c++, variables with such operators cannot be passed as argument to function. package main import ( "fmt" ) func abcd(a int, b int) { fmt.Println(a," &...

Go • Methods

Simple stubbing

Sometimes there are sections of code that are difficult to test, such as accessing a database, or interacting with the user. You can stub out those sections of code, allowing the rest of the code to be tested. Let's start with a class that prompts the user. For simplicity, it has only two methods...

phpunit • Test Doubles (Mocks and Stubs)

Creating a new project from the Game template.

To set up a default SceneKit project you can use the Game Template.

scenekit • Getting started with scenekit

INSERT data and RETURING values

If you are inserting data into a table with an auto increment column and if you want to get the value of the auto increment column. Say you have a table called my_table: CREATE TABLE my_table ( id serial NOT NULL, -- serial data type is auto incrementing four-byte integer name character varying...

postgresql • INSERT

Installing Payara Server Full

Prerequisites JDK 1.7 or later installed. You can find the Oracle JDK's here. Steps Download Payara Server Full. Unzip the Payara Server at some location on your computer. We will use C:\payara41 as INSTALL_DIR for Windows users and /payara41 for Linux/Mac users. Starting / stopping Pa...

java-ee • Getting started with java-ee

Building my First JavaEE Application (Hello World)

Let's understand something. JavaEE consists of a number of specifications. When you install an Application Server (Payara for example), you install all of the specifications at once. For example there's a specification for an ORM called JPA (Java Persistence API), a specification to build Component ...

java-ee • Getting started with java-ee