Tutorial by Examples: f

If you have a ActiveRecord User class with name and email attributes, you could create a factory for it by making the FactoryGirl guess it: FactoryGirl.define do factory :user do # it will guess the User class name "John" email "[email protected]" end end ...

Here is a simple proof by induction. Require Import Coq.Setoids.Setoid. Require Import Coq.Arith.Lt. (* A number is less than or equal to itself *) Theorem aLTEa : forall a, a <= a. auto with arith. (* This follows by simple arithmetic *) Qed. Theorem simplALTE : forall a ...

Consider the following code: public async Task MethodA() { await MethodB(); // Do other work } public async Task MethodB() { await MethodC(); // Do other work } public async Task MethodC() { // Or await some other async work await Task.Delay(100); } ...

It parses the data from the %%GLOBAL_ConversionCode%% template variable, and as such this script should be inserted in order.html immediately after the %%GLOBAL_ConversionCode%% variable. This was originally intended for the Blueprint theme framework and, as such, may not work on Stencil. <scrip...

The following example shows how to apply custom fonts to a Navigation Bar and includes fixes for some quirky behaviors found in Xcode. One also may apply the custom fonts to any other UIControls such as UILabels, UIButtons, and more by using the attributes inspector after the custom font is added to...

In Coq, destruct more or less corresponds to a case analysis. It is similar to induction except that there's no induction hypothesis. Here is a (admittedly rather trivial) example of this tactic: Require Import Coq.Arith.Lt. Theorem atLeastZero : forall a, 0 <= a. Proof. intros. destr...

By default, floating point operations on float and double do not strictly adhere to the rules of the IEEE 754 specification. An expression is allowed to use implementation-specific extensions to the range of these values; essentially allowing them to be more accurate than required. strictfp disable...

The window.confirm() method displays a modal dialog with an optional message and two buttons, OK and Cancel. Now, let's take the following example: result = window.confirm(message); Here, message is the optional string to be displayed in the dialog and result is a boolean value indicating wheth...

from subprocess import check_call ok = check_call(['ffmpeg','-i','input.mp3','output.wav']) if ok: with open('output.wav', 'rb') as f: wav_file = f.read() note: http://superuser.com/questions/507386/why-would-i-choose-libav-over-ffmpeg-or-is-there-even-a-difference What are ...

Flask's built-in webserver is able to serve static assets, and this works fine for development. However, for production deployments that are using something like uWSGI or Gunicorn to serve the Flask application, the task of serving static files is one that is typically offloaded to the frontend webs...

# from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer # python2 from http.server import BaseHTTPRequestHandler, HTTPServer # python3 class HandleRequests(BaseHTTPRequestHandler): def _set_headers(self): self.send_response(200) self.send_header('Content-type', 'text...

Problems may happen when multiple threads try to access a resource. For a simple example, suppose we have a thread that adds one to a variable. It does this by first reading the variable, adding one to it, then storing it back. Suppose we initialize this variable to 1, then create two instances of t...

double res[MAX]; int i; #pragma omp parallel { #pragma omp for for (i=0;i< MAX; i++) { res[i] = huge(); } } The for loop will be executed in parallel. huge() is some method which can take too long to get execute. OpenMP supports a shortcut to write the ab...

So the main goal of this function is to : Be standalone because it needs to be written in the main VbScript file and cannot be in an included file (because it defines the include function) Provide enough information if something goes wrong (ie. the file that was being included, the error that oc...

To include a file in another file, just use the one liner : IncludeFile "myOtherFile.vbs"

NgFor provides Some values that can be aliased to local variables index -(variable) position of the current item in the iterable starting at 0 first -(boolean) true if the current item is the first item in the iterable last -(boolean) true if the current item is the last item in the iterable ...

To generate schema, view, controller, migration file for the repository, default CRUD templates and test files for a model (like a scaffolding in Rails) one can use phoenix.gen.html mix task like this: mix phoenix.gen.html Book books title note:text pages:integer author_id:references:authors Wh...

Let's say you want to show a text field (announcement) based on the time (a scheduled notification message for instance). You need two date-time fields. In our example, one is called start_date and the other end_date. <?php $DateNow = date('Y-m-d H:i:s'); $DateStart = get_field('start_date',...

This is a quick guide to get Robot Framework 3.0 working on a Windows machine using Python 2.7.11 - It does not go into too much depth on the why and how, it simply gets you up and running. First things are first, let't go and install Python! Download Python 2.7.11 for Windows. (Windows x86-64 ...

There are many ways of creating DataFrames. They can be created from local lists, distributed RDDs or reading from datasources. Using toDF By importing spark sql implicits, one can create a DataFrame from a local Seq, Array or RDD, as long as the contents are of a Product sub-type (tuples and ca...