Tutorial by Examples: le

Stream is especially useful when you want to run multiple operations on a collection. This is because Stream is lazy and only does one iteration (whereas Enum would do multiple iterations, for example). numbers = 1..100 |> Stream.map(fn(x) -> x * 2 end) |> Stream.filter(fn(x) -> rem(x...

This example is a snippet taken from the Extending Django User Profile like a Pro from django.db import models from django.contrib.auth.models import User from django.db.models.signals import post_save class UserProfile(models.Model): user = models.OneToOneField(User, related_name='user'...

Use the UseCors() extension method on the IApplicationBuilder in the Configure method to apply the CORS policy to all requests. public void ConfigureServices(IServiceCollection services) { services.AddMvc(); services.AddCors(); } public void Configure(IApplicationBuilder app) { ...

To enable a certain CORS policy for specific controllers you have to build the policy in the AddCors extension within the ConfigureServices method: services.AddCors(cors => cors.AddPolicy("AllowAll", policy => { policy.AllowAnyOrigin() .AllowAnyMethod() ...

Open the psql command line tool connected to the database where your table is. Then type the following command: \d tablename To get extended information type \d+ tablename If you have forgotten the name of the table, just type \d into psql to obtain a list of tables and views in the current ...

Let's say you have a table called person: CREATE TABLE person ( person_id BIGINT NOT NULL, last_name VARCHAR(255) NOT NULL, first_name VARCHAR(255), age INT NOT NULL, PRIMARY KEY (person_id) ); You can create a new table of people over 30 like this: CREATE TABLE p...

Consider entities Customer, Purchase and PurchaseItem as follows: public class Customer { public string Id { get; set } // A unique Id that identifies customer public string Name {get; set; } } public class Purchase { public string Id { get; set } public string CustomerId...

PropertyInfo[] stringProps = typeof (string).GetProperties();//string properties PropertyInfo[] builderProps = typeof(StringBuilder).GetProperties();//stringbuilder properties var query = from s in stringProps join b in builderProps on new { s.Name, s.P...

You can insert multiple rows in the database at the same time: INSERT INTO person (name, age) VALUES ('john doe', 25), ('jane doe', 20);

You can insert data in a table as the result of a select statement: INSERT INTO person SELECT * FROM tmp_person WHERE age < 30; Note that the projection of the select must match the columns required for the insert. In this case, the tmp_person table has the same columns as person.

RoboGuice is a framework that brings the simplicity and ease of Dependency Injection to Android, using Google's own Guice library. @ContentView(R.layout.main) class RoboWay extends RoboActivity { @InjectView(R.id.name) TextView name; @InjectView(R.id.thumbnail) Image...

Add the following pom to the dependencies section of your gradle build file : project.dependencies { compile 'org.roboguice:roboguice:3.+' provided 'org.roboguice:roboblender:3.+' }

It was common practice to use NSRunLoop to show modal UIAlertView to block code execution until user input is processed in iOS; until Apple released the iOS7, it broke few existing apps. Fortunately, there is a better way of implementing it with C#’s async/await. Here’s the new code taking advantag...

User input Imagine you want a user to enter a number via input. You want to ensure that the input is a number. You can use try/except for this: Python 3.x3.0 while True: try: nb = int(input('Enter a number: ')) break except ValueError: print('This is not a num...

To create a variable: variableType variableName; For example: int a; To create a variable and initialize it: variableType variableName = initialValue; For example: int a = 2;

If you have a variable declared before, you can assign some value to it: For example: int a; // declared previously a = 2; Or change the value: int a = 3; // initalized previously a = 2;

char : signed 1-byte character value byte : unsigned 8-bit integer int : signed 16-bit (on ATMEGA based boards) or 32-bit (on Arduino Due) integer unsigned int : unsigned 16-bit (on ATMEGA based boards) or 32-bit (on Arduino Due) integer long : signed 32-bit integer unsigned long : unsigned 3...

DECLARE @Employees TABLE ( EmployeeID INT NOT NULL PRIMARY KEY, FirstName NVARCHAR(50) NOT NULL, LastName NVARCHAR(50) NOT NULL, ManagerID INT NULL ) When you create a normal table, you use CREATE TABLE Name (Columns) syntax. When creating a table variable, you use DECLARE @...

DECLARE @VariableName INT SET @VariableName = 1 PRINT @VariableName 1 Using SET, you can only update one variable at a time.

Using SELECT, you can update multiple variables at once. DECLARE @Variable1 INT, @Variable2 VARCHAR(10) SELECT @Variable1 = 1, @Variable2 = 'Hello' PRINT @Variable1 PRINT @Variable2 1 Hello When using SELECT to update a variable from a table column, if there are multiple values, it wi...