Tutorial by Examples

First, add relevant dependencies into the build.gradle file. dependencies { .... compile 'com.squareup.retrofit2:retrofit:2.3.0' compile 'com.squareup.retrofit2:converter-gson:2.3.0' compile 'com.squareup.retrofit2:adapter-rxjava:2.3.0' .... } Then create the model you ...

Installing linq-to-sql: Right-click the App_Code folder and then click Add New Item. The Add New Item dialog box is displayed. Under Visual Studio installed templates, select the LINQ to SQL Classes template and rename the file Tasks.dbml. Click Add. OR: Under VS2102, in your solution explorer, r...

import pandas as pd Create a DataFrame from a dictionary, containing two columns: numbers and colors. Each key represent a column name and the value is a series of data, the content of the column: df = pd.DataFrame({'numbers': [1, 2, 3], 'colors': ['red', 'white', 'blue']}) Show contents of d...

Create a DataFrame of random numbers: import numpy as np import pandas as pd # Set the seed for a reproducible sample np.random.seed(0) df = pd.DataFrame(np.random.randn(5, 3), columns=list('ABC')) print(df) # Output: # A B C # 0 1.764052 0.400157 0.9787...

Single line comments are preceded by --, and go until the end of the line: SELECT * FROM Employees -- this is a comment WHERE FName = 'John'

Multi-line code comments are wrapped in /* ... */: /* This query returns all employees */ SELECT * FROM Employees It is also possible to insert such a comment into the middle of a line: SELECT /* all columns: */ * FROM Employees

Imports System.Reflection Public Class PropertyExample Public Function GetMyProperties() As PropertyInfo() Dim objProperties As PropertyInfo() objProperties = Me.GetType.GetProperties(BindingFlags.Public Or BindingFlags.Instance) Return objProperties End Fun...

As Handlers are used to send Messages and Runnables to a Thread's message queue it's easy to implement event based communication between multiple Threads. Every Thread that has a Looper is able to receive and process messages. A HandlerThread is a Thread that implements such a Looper, for example th...

Naming Convention Notifications are identified by global NSString objects whose names are composed in this way: Name of associated class + Did | Will + UniquePartOfName + Notification For example: NSApplicationDidBecomeActiveNotification NSWindowDidMiniaturizeNotification NSTextViewDidChange...

Swift 2.3 //Remove observer for single notification NSNotificationCenter.defaultCenter().removeObserver(self, name: "TestNotification", object: nil) //Remove observer for all notifications NotificationCenter.defaultCenter().removeObserver(self) Swift 3 //Remove observer for s...

Swift NSNotificationCenter.defaultCenter().postNotificationName("TestNotification", object: self) Objective-C [[NSNotificationCenter defaultCenter] postNotificationName:@"TestNotification" object:nil];

Swift let userInfo: [String: AnyObject] = ["someKey": myObject] NSNotificationCenter.defaultCenter().postNotificationName("TestNotification", object: self, userInfo: userInfo) Objective-C NSDictionary *userInfo = [NSDictionary dictionaryWithObject:myObject forKey:@"som...

Swift func testNotification(notification: NSNotification) { let userInfo = notification.userInfo let myObject: MyObject = userInfo["someKey"] } Objective-C - (void)testNotification:(NSNotification *)notification { NSDictionary *userInfo = notification.userInfo; My...

Use Ctrl + C, Ctrl + C to exit iex(1)> BREAK: (a)bort (c)ontinue (p)roc info (i)nfo (l)oaded (v)ersion (k)ill (D)b-tables (d)istribution Use Ctrl+ \ to immediately exit

iex(1)> i :ok Term :ok Data type Atom Reference modules Atom iex(2)> x = "mystring" "mystring" iex(3)> i x Term "mystring" Data type BitString Byte size 8 Description This is a string: a UTF-8 encoded binary. It's printed surround...

#You can use pattern matching to run different #functions based on which parameters you pass #This example uses pattern matching to start, #run, and end a recursive function defmodule Counter do def count_to do count_to(100, 0) #No argument, init with 100 end def ...

Syntax: REPLACE( String to search , String to search for and replace , String to place into the original string ) Example: SELECT REPLACE( 'Peter Steve Tom', 'Steve', 'Billy' ) --Return Values: Peter Billy Tom

Creating a DB and a Table DROP DATABASE IF EXISTS books_db; CREATE DATABASE books_db WITH ENCODING='UTF8' TEMPLATE template0; DROP TABLE IF EXISTS books; CREATE TABLE books ( id SERIAL PRIMARY KEY, client TEXT NOT NULL, data JSONb NOT NULL ); Populating the DB INSERT INTO books...

A standard toast notification appears at the bottom of the screen aligned in horizontal centre. You can change this position with the setGravity(int, int, int). This accepts three parameters: a Gravity constant, an x-position offset, and a y-position offset. For example, if you decide that the toas...

p { margin:1px; /* 1px margin in all directions */ /*equals to:*/ margin:1px 1px; /*equals to:*/ margin:1px 1px 1px; /*equals to:*/ margin:1px 1px 1px 1px; } Another exapmle: p{ margin:10px 15px; /...