Tutorial by Examples: g

A common mistake is to forget surrounding compound function arguments with parentheses, leading to type errors. # string_of_int 1+1;; Error: This expression has type string but an expression was expected of type int This is because of the precedence. In fact, the above evaluates to # (string...

Redis provides the SCAN command to iterate over the keys in the database matching a particular pattern. Redis supports glob style pattern matching in the SCAN command. The SCAN command provides a cursor-based iterator over the Redis keyspace. The iterative call sequence to SCAN starts with the us...

The redis-py client provides two classes StrictRedis and Redis to establish a basic connection to a Redis database. The Redis class is provided for backwards compatibility and new projects should use the StrictRedis class. One of the recommended ways to establish a connection, is to define the con...

file_unzip = 'filename.zip' unzip = zipfile.ZipFile(file_unzip, 'r') unzip.extractall() unzip.close()

file_untar = 'filename.tar.gz' untar = tarfile.TarFile(file_untar) untar.extractall() untar.close()

Generic type parameters are commonly defined at the class or interface level, but methods and (rarely) constructors also support declaring type parameters bound to the scope of a single method call. class Utility // no generics at the class level { @SafeVarargs public static <T> T ...

Several commands allow you to work with Strings representing integer values. A user can set the integer value of a key using the command: SET intkey 2 The set command will create the key if necessary or update it if it already exists. The value of an integer key can be updated on the server us...

Note: The output.library and name (in DllPlugin) must be the same. const path = require('path'); const webpack = require('webpack'); const ExtractTextPlugin = require('extract-text-webpack-plugin'); const extractCSS = new ExtractTextPlugin('vendor.css'); const isDevelopment = process.env.NODE_E...

Note: manifest (in DllReferencePlugin) should reference path (defined in DllPlugin) const webpack = require('webpack'); const path = require('path'); const isDevelopment = process.env.NODE_ENV !== 'production'; const ExtractTextPlugin = require('extract-text-webpack-plugin'); const extractCSS...

using Microsoft.AspNetCore.Http; using System; using System.Diagnostics; using System.IO; using System.Linq; using System.Threading.Tasks; using Microsoft.AspNet.Http.Internal; using Microsoft.AspNetCore.Http.Internal; public class LoggerMiddleware { private readonly Reques...

Starting JShell Before trying to start JShell, make sure your JAVA_HOME environment variable points to a JDK 9 installation. To start JShell, run the following command: $ jshell If all goes well, you should see a jshell> prompt. Exiting JShell To exit JShell, run the following command from...

The DividerItemDecoration is a RecyclerView.ItemDecoration that can be used as a divider between items. DividerItemDecoration mDividerItemDecoration = new DividerItemDecoration(context, mLayoutManager.getOrientation()); recyclerView.addItemDecoration(mDividerItemDecoration); It su...

Android O changes the way to work with fonts. Android O introduces a new feature, called Fonts in XML, which allows you to use fonts as resources. This means, that there is no need to bundle fonts as assets. Fonts are now compiled in an R file and are automatically available in the system as a reso...

The keyword function can be used to initiate pattern-matching on the the last argument of a function. For example, we can write a function called sum, which computes the sum of a list of integers, this way let rec sum = function | [] -> 0 | h::t -> h + sum t ;; val sum : int list -&...

Drop/Delete your database If you are using SQLite for your database, just delete this file. If you are using MySQL/Postgres or any other database system, you will have to drop the database and then recreate a fresh database. You will now need to delete all the migrations file except "init.py...

To access complete schema of server db instead of single table. Follow below steps: Create EXTENSION : CREATE EXTENSION postgres_fdw; Create SERVER : CREATE SERVER server_name FOREIGN DATA WRAPPER postgres_fdw OPTIONS (host 'host_ip', dbname 'db_name', port 'port_numb...

For this example, we will used 4 bodies and will show only the last 8 bits of the bit masks for simplicity. The 4 bodies are 3 SKSpriteNodes, each with a physics body and a boundary: let edge = frame.insetBy(dx: 0, dy: 0) physicsBody = SKPhysicsBody(edgeLoopFrom: edge) Note that the 'ed...

The basic unit of code used by JShell is the snippet, or source entry. Every time you declare a local variable or define a local method or class, you create a snippet whose name is the identifier of the variable/method/class. At any time, you can edit a snippet you have created with the /edit comman...

1) IP based vhosts <VirtualHost 192.168.13.37> ServerName example.com DocumentRoot /var/www/domains/example.com/html ErrorLog /var/log/example.com/error.log CustomLog /var/log/example.com/access.log common </VirtualHost> <VirtualHost 192.168.47.11> ...

Redis allow you to use the String data type to store floating point numbers. A user can set the float value of a key using the command: SET floatkey 2.0 The set command will create the key if necessary or update it if it already exists. The value of the key can be updated on the server using e...