Tutorial by Examples: w

Another powerful & mature concurrency tool in Haskell is Software Transactional Memory, which allows for multiple threads to write to a single variable of type TVar a in an atomic manner. TVar a is the main type associated with the STM monad and stands for transactional variable. They're used m...

Zip two arrays into an array of pairs: Prelude Data.Vector> Data.Vector.zip y y fromList [(0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9),(10,10),(11,11)] :: Data.Vector.Vector

Most of the magic of destructuring uses the splat (*) operator. ExampleResult / commenta, b = [0,1]a=0, b=1a, *rest = [0,1,2,3]a=0, rest=[1,2,3]a, * = [0,1,2,3]a=0   Equivalent to .first*, z = [0,1,2,3]z=3   Equivalent to .last

Vim knows The Answer: :help 42 Vim will open the usr_42.txt document from the manual and show the following text: What is the meaning of life, the universe and everything? 42 Douglas Adams, the only person who knew what this question really was about is now dead, unfortunately. So now you m...

These rules apply only if you use manual reference counting! You own any object you create By calling a method whose name begins with alloc, new, copy or mutableCopy. For example: NSObject *object1 = [[NSObject alloc] init]; NSObject *object2 = [NSObject new]; NSObject *object3 = [object2 ...

Here is a quick example of using multiple forms in one Django view. from django.contrib import messages from django.views.generic import TemplateView from .forms import AddPostForm, AddCommentForm from .models import Comment class AddCommentView(TemplateView): post_form_class = AddPo...

A Haskell project can either use the system wide packages or use a sandbox. A sandbox is an isolated package database and can prevent dependency conflicts, e. g. if multiple Haskell projects use different versions of a package. To initialize a sandbox for a Haskell package go to its directory and r...

After you have opened a split window in vim (as demonstrated by many examples under this tag) then you will likely want to control windows quickly. Here is how to control split windows using keyboard shortcuts. Move to split Above/Below: Ctrl + w and k Ctrl + w and j Move to split Left/Right...

The Window Object contains the following properties. PropertyDescriptionwindow.closedWhether the window has been closedwindow.lengthNumber of <iframe> elements in windowwindow.nameGets or sets the name of the windowwindow.innerHeightHeight of windowwindow.innerWidthWidth of windowwindow.scree...

python-social-auth is a framework that simplifies the social authentication and authorization mechanism. It contains many social backends (Facebook, Twitter, Github, LinkedIn, etc.) INSTALL First we need to install the python-social-auth package with pip install python-social-auth or download ...

import pandas as pd import numpy as np import matplotlib.pyplot as plt # I want 7 days of 24 hours with 60 minutes each periods = 7 * 24 * 60 tidx = pd.date_range('2016-07-01', periods=periods, freq='T') # ^ ^ # | ...

C++11 The std::is_same<T, T> type relation is used to compare two types. It will evaluate as boolean, true if the types are the same and false if otherwise. e.g. // Prints true on most x86 and x86_64 compilers. std::cout << std::is_same<int, int32_t>::value << "\n&qu...

aiohttp provides asynchronous websockets. Python 3.x3.5 import asyncio from aiohttp import ClientSession with ClientSession() as session: async def hello_world(): websocket = await session.ws_connect("wss://echo.websocket.org") websocket.send_str("Hell...

aiohttp.ClientSession may be used as a parent for a custom WebSocket class. Python 3.x3.5 import asyncio from aiohttp import ClientSession class EchoWebSocket(ClientSession): URL = "wss://echo.websocket.org" def __init__(self): super().__init__() self....

<?php $to = '[email protected]'; $subject = 'Email Subject'; $message = 'This is the email message body'; $attachment = '/path/to/your/file.pdf'; $content = file_get_contents($attachment); /* Attachment content transferred in Base64 encoding MUST be split into chunk...

<?php $mail = new PHPMailer(); $mail->From = "[email protected]"; $mail->FromName = "Full Name"; $mail->addReplyTo("[email protected]", "Reply Address"); $mail->Subject = "Subject Text"; $mail->Body = "This is...

<?php $sendgrid = new SendGrid("YOUR_SENDGRID_API_KEY"); $email = new SendGrid\Email(); $email->addTo("[email protected]") ->setFrom("[email protected]") ->setSubject("Subject Text") ->setText("This is a ...

Since lots of beginners are confused about cloud hosting.I am writing this guide to walk through setting meteor on aws with ubuntu os. If you already have your instance running feel free to skip this step and go straight to installing meteor on aws. Login into AWS Console.Select EC2. Go to EC2 Dash...

Some examples for a window of size 3: ;; Naïve attempt: (loop for (first second third) on '(1 2 3 4 5) do (print (* first second third))) ;; prints 6 24 60 then Errors on (* 4 5 NIL) ;; We will try again and put our attempt into a function (defun loop-3-window1 (function list) (loop...

If the size of your content is fixed, you can use absolute positioning to 50% with margin that reduces half of your content's width and height: HTML <div class="center"> Center vertically and horizontally </div> CSS .center { position: absolute; background...