Tutorial by Examples: le

context.fillStyle=color Sets the color that will be used to fill the interior of the current path. These are color options (these must be quoted): A CSS named color, for example context.fillStyle='red' A hex color, for example context.fillStyle='#FF0000' An RGB color, for example ...

Use itertools.chain to create a single generator which will yield the values from several generators in sequence. from itertools import chain a = (x for x in ['1', '2', '3', '4']) b = (x for x in ['x', 'y', 'z']) ' '.join(chain(a, b)) Results in: '1 2 3 4 x y z' As an alternate constructo...

You can check for syntax errors and referenced files in an NGINX configuration file before running it with: nginx -t Alternatively you can run service script service nginx configtest While both of these commands will tell you if your new nginx configuration is ok [without killing your curren...

nginx -c <file name> Start NGINX with an explicit configuration file.

Enabling gzip compression can reduce the size of the transferred response by up to 90%, which can significantly reduce the amount of time to download the resource, reduce data usage for the client, and improve the time to first render of your pages. — PageSpeed Insights Compression can be ena...

Fetching resources over the network is both slow and expensive: the download may require multiple roundtrips between the client and server, which delays processing and may block rendering of page content, and also incurs data costs for the visitor. All server responses should specify a caching p...

A condition variable is a primitive used in conjunction with a mutex to orchestrate communication between threads. While it is neither the exclusive or most efficient way to accomplish this, it can be among the simplest to those familiar with the pattern. One waits on a std::condition_variable with...

int main (void) { const int foo_readonly = 10; int *foo_ptr; foo_ptr = (int *)&foo_readonly; /* (1) This casts away the const qualifier */ *foo_ptr = 20; /* This is undefined behavior */ return 0; } Quoting ISO/IEC 9899:201x, section 6.7.3 §2: If an attempt i...

installing npm install web-component-tester --save-dev setting up wct.conf.js module.exports = { verbose: true, plugins: { local: { browsers: ['chrome'] } } }; running node node_modules/web-component-tester/bin/wct test/index.html <html...

A variable declared constexpr is implicitly const and its value may be used as a constant expression. Comparison with #define A constexpr is type-safe replacement for #define based compile-time expressions. With constexpr the compile-time evaluated expression is replaced with the result. For examp...

class Foldable t where {-# MINIMAL foldMap | foldr #-} foldMap :: Monoid m => (a -> m) -> t a -> m foldMap f = foldr (mappend . f) mempty foldr :: (a -> b -> b) -> b -> t a -> b foldr f z t = appEndo (foldMap (Endo #. f) t) z -- and a nu...

class (Functor t, Foldable t) => Traversable t where {-# MINIMAL traverse | sequenceA #-} traverse :: Applicative f => (a -> f b) -> t a -> f (t b) traverse f = sequenceA . fmap f sequenceA :: Applicative f => t (f a) -> f (t a) sequenceA = t...

<?xml version="1.0" encoding="UTF-8"?> <Configuration> <Appenders> <Console name="STDOUT" target="SYSTEM_OUT"> <PatternLayout pattern="%d %-5p [%t] %C{2} %m%n"/> </Console> </Appenders&gt...

A method can take an array parameter and destructure it immediately into named local variables. Found on Mathias Meyer's blog. def feed( amount, (animal, food) ) p "#{amount} #{animal}s chew some #{food}" end feed 3, [ 'rabbit', 'grass' ] # => "3 rabbits chew some gra...

By default the Custom Tool property for a VB resource file is VbMyResourcesResXFileCodeGenerator. However, with this code generator the view (XAML) will not be able to access the resources. To solve this problem add Public before the Custom Tool property value. To select the Resources.resx file in ...

Sometimes you might accidentally run something in the shell that ends up waiting forever, and thus blocking the shell: iex(2)> receive do _ -> :stuck end In that case, press Ctrl-g. You'll see: User switch command Enter these commands in order: k (to kill the shell process) s (to st...

Computed observables are functions that can "watch" or "react" to other observables on the view model. The following example shows how you would display the total number of users and the average age. Note: The example below can also make use of pureComputed() (introduced in v3....

You can return an instance of Tuple class from your function with two template parameters as Tuple<string, MyClass>: public Tuple<string, MyClass> FunctionWith2ReturnValues () { return Tuple.Create("abc", new MyClass()); } And read the values like below: Console.Wri...

There are a couple of default recognizers available in Xamarin.Forms, one of them is the TapGestureRecognizer. You can add them to virtually any visual element. Have a look at a simple implementation which binds to an Image. Here is how to do it in code. var tappedCommand = new Command(() => {...

The System.String.Join method allows to concatenate all elements in a string array, using a specified separator between each element: string[] words = {"One", "Two", "Three", "Four"}; string singleString = String.Join(",", words); // singleString =...