Tutorial by Examples: a

If you already have sbt installed I find it easier to create a minimal Play project without activator. Here's how. # create a new folder mkdir myNewProject # launch sbt sbt When previous steps are completed, edit build.sbt and add the following lines name := """myProjectName&q...

CREATE TABLE table_name ( id INT NOT NULL AUTO_INCREMENT, json_col JSON, PRIMARY KEY(id) );

INSERT INTO table_name (json_col) VALUES ('{"City": "Galle", "Description": "Best damn city in the world"}'); That's simple as it can get but note that because JSON dictionary keys have to be surrounded by double quotes the entire thing should b...

C++11 Basic example: template<typename T> using pointer = T*; This definition makes pointer<T> an alias of T*. For example: pointer<int> p = new int; // equivalent to: int* p = new int; Alias templates cannot be specialized. However, that functionality can be obtained indi...

import os, sys from openpyxl import Workbook from datetime import datetime dt = datetime.now() list_values = [["01/01/2016", "05:00:00", 3], \ ["01/02/2016", "06:00:00", 4], \ ["01/03/2016", "07:00:00",...

Cryptography is something very hard and after spending a lot of time reading different examples and seeing how easy it is to introduce some form of vulnerability I found an answer originally written by @jbtule that I think is very good. Enjoy reading: "The general best practice for symmetric e...

Giving your list a type To create a list you need a type (any class, e.g. String). This is the type of your List. The List will only store objects of the specified type. For example: List<String> strings; Can store "string1", "hello world!", "goodbye", etc, b...

The List API has eight methods for positional access operations: add(T type) add(int index, T type) remove(Object o) remove(int index) get(int index) set(int index, E element) int indexOf(Object o) int lastIndexOf(Object o) So, if we have a List: List<String> strings = new ArrayL...

For the example, lets say that we have a List of type String that contains four elements: "hello, ", "how ", "are ", "you?" The best way to iterate over each element is by using a for-each loop: public void printEachElement(List<String> list){ for...

The implementation of INotifyPropertyChange can be error-prone, as the interface requires specifying property name as a string. In order to make the implementation more robust, an attribute CallerMemberName can be used. class C : INotifyPropertyChanged { // backing field int offset; ...

mysqladmin -u root -p'old-password' password 'new-password'

Useful for scripting to drop all tables and deletes the database: mysqladmin -u[username] -p[password] drop [database] Use with extreme caution. To DROP database as a SQL Script (you will need DROP privilege on that database): DROP DATABASE database_name or DROP SCHEMA database_name

#include <iostream> long double operator"" _km(long double val) { return val * 1000.0; } long double operator"" _mi(long double val) { return val * 1609.344; } int main() { std::cout << "3 km = " << 3.0_km << " m...

Batch execution using java.sql.PreparedStatement allows you to execute a single DML statement with multiple sets of values for its parameters. This example demonstrates how to prepare an insert statement and use it to insert multiple rows in a batch. Connection connection = ...; // obtained earl...

Batch execution using java.sql.Statement allows you to execute multiple DML statements (update, insert, delete) at once. This is achieved by creating a single statement object, adding the statements to execute, and then execute the batch as one. Connection connection = ...; // obtained earlier c...

Compare the definition of Free to that of Fix: data Free f a = Return a | Free (f (Free f a)) newtype Fix f = Fix { unFix :: f (Fix f) } In particular, compare the type of the Free constructor with the type of the Fix constructor. Free layers up a functor just like Fix, except ...

options = { "x": ["a", "b"], "y": [10, 20, 30] } Given a dictionary such as the one shown above, where there is a list representing a set of values to explore for the corresponding key. Suppose you want to explore "x"="a" w...

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <rect x="10" y="10" width="50" height="100" stroke="black" stroke-width="5" fill="none" /> </svg> R...

The width and height attributes designate the dimensions of the rectangle. These values are in pixels by default The fill value sets the color for the rectangle. If no value for fill is specified, black is used by default <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="h...

If you use a dictionary as an iterator (e.g. in a for statement), it traverses the keys of the dictionary. For example: d = {'a': 1, 'b': 2, 'c':3} for key in d: print(key, d[key]) # c 3 # b 2 # a 1 The same is true when used in a comprehension print([key for key in d]) # ['c', 'b', '...