Tutorial by Examples: p

Self types can be used in traits and classes to define constraints on the concrete classes it is mixed to. It is also possible to use a different identifier for the this using this syntax (useful when outer object has to be referenced from an inner object). Assume you want to store some objects. Fo...

#!/bin/bash FILENAME="/etc/passwd" while IFS=: read -r username password userid groupid comment homedir cmdshell do echo "$username, $userid, $comment $homedir" done < $FILENAME In unix password file, user information is stored line by line, each line consisting of i...

In Object Oriented Programming a common task is to compose objects (values). In Functional Programming it is as common task to compose values as well as functions. We are used to compose values from our experience of other programming languages using operators like +, -, *, / and so on. Value co...

In a statically typed language like F# we work with types well-known at compile-time. We consume external data sources in a type-safe manner using type providers. However, occassionally there's need to use late binding (like dynamic in C#). For instance when working with JSON documents that have...

let seq = seq {0..10} s |> Seq.map (fun x -> x * 2) > val it : seq<int> = seq [2; 4; 6; 8; ...] Apply a function to every element of a sequence using Seq.map

A for loop iterates from the starting value to the ending value inclusive. program SimpleForLoop; {$APPTYPE CONSOLE} var i : Integer; begin for i := 1 to 10 do WriteLn(i); end. Output: 1 2 3 4 5 6 7 8 9 10

This example demonstrates POSIX Timer usage with CLOCK_REALTIME clock and SIGEV_THREAD notification method. #include <stdio.h> /* for puts() */ #include <string.h> /* for memset() */ #include <unistd.h> /* for sleep() */ #include <stdlib.h> /* for EXIT_SUCCESS */ #inc...

C# using OpenQA.Selenium using OpenQA.Selenium.Chrome; using System.Threading; namespace WebDriver Tests { class WebDriverWaits { static void Main() { IWebDriver driver = new ChromeDriver(@"C:\WebDriver"); driver.Na...

Using sync.Pool structure we can pool objects and reuse them. package main import ( "bytes" "fmt" "sync" ) var pool = sync.Pool{ // New creates an object when the pool has nothing available to return. // New must return an interface{} to...

The main app file loads any routes files in which you would like to define routes. To do so we need the following directory structure: app.js routes/index.js routes/users.js app.js var express = require('express'); var app = express(); app.use('/', require('./routes/index')); app.use('/us...

Here we consider sums of the form a + b + a + b + ... a vs. a + b + a + b + ... b To visualize these sums, imagine a section of fence alternating between posts and rails. Three scenarios are possible. Imagine a section of fence with posts at each end, connected by rails. n rails require...

Normally Android-SQLiteOpenHelper does not allow fully qualified path names where the database should be stored. So public database files are not possible. You can use the SQLiteOpenHelper with a custom path if you provide a custom ContextClass and if you have write access in the target directory. ...

Checking whether the current date contains the symbol for AM or PM Objective-C NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; [formatter setLocale:[NSLocale currentLocale]]; [formatter setDateStyle:NSDateFormatterNoStyle]; [formatter setTimeStyle:NSDateFormatterShortStyle]; NSStr...

Declare JNDI resource in tomcat's server.xml, using the Tomcat JDBC connection pool: <GlobalNamingResources> <Resource name="jdbc/DatabaseName" factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" auth="Container" ...

Pooling provides a higher level abstraction of the Worker functionality, including the management of references in the way required by pthreads. From: http://php.net/manual/en/class.pool.php Pools and workers provide an higher level of control and ease of creating multi-threaded <?php // T...

If you wish to make a complete backup of a large MySql installation and do not have sufficient local storage, you can dump and compress it directly to an Amazon S3 bucket. It's also a good practice to do this without having the DB password as part of the command: mysqldump -u root -p --host=localho...

Immediately invoked function expressions can be used to create a private scope while producing a public API. var Module = (function() { var privateData = 1; return { getPrivateData: function() { return privateData; } }; })(); Module.getPrivateData(); // 1 Module.priva...

Add the gradle dependency in app-level build.gradle compile 'com.android.volley:volley:1.0.0' Also, add the android.permission.INTERNET permission to your app's manifest. **Create Volley RequestQueue instance singleton in your Application ** public class InitApplication extends Application { ...

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Iterator methods can be broken into two distinct groups: Adapters Adapters take an iterator and return another iterator // Iterator Adapter // | | let my_map = (1..6).map(|x| x * x); println!("{:?}", my_map); Output Map { iter: 1..6 } Note that the v...