Tutorial by Examples: d

Creating Gradient UIImage with colors in CGRect Swift: extension UIImage { static func gradientImageWithBounds(bounds: CGRect, colors: [CGColor]) -> UIImage { let gradientLayer = CAGradientLayer() gradientLayer.frame = bounds gradientLayer.colors = colors ...

+ (CALayer *)gradientBGLayerForBounds:(CGRect)bounds colors:(NSArray *)colors { CAGradientLayer * gradientBG = [CAGradientLayer layer]; gradientBG.frame = bounds; gradientBG.colors = colors; return gradientBG; }

Use threading.Thread to run a function in another thread. import threading import os def process(): print("Pid is %s, thread id is %s" % (os.getpid(), threading.current_thread().name)) threads = [threading.Thread(target=process) for _ in range(4)] for t in threads: t.sta...

As all threads are running in the same process, all threads have access to the same data. However, concurrent access to shared data should be protected with a lock to avoid synchronization issues. import threading obj = {} obj_lock = threading.Lock() def objify(key, val): print("O...

Informally, a monad is a container of elements, notated as F[_], packed with 2 functions: flatMap (to transform this container) and unit (to create this container). Common library examples include List[T], Set[T] and Option[T]. Formal definition Monad M is a parametric type M[T] with two operatio...

Returns the start index of a the first occurrence of string expression inside another string expression. Parameters list: String to find (up to 8000 chars) String to search (any valid character data type and length, including binary) (Optional) index to start. A number of type int or big int. ...

Returns the integer value representing the Unicode value of the first character of the input expression. Parameters: Unicode character expression. Any valid nchar or nvarchar expression. SELECT UNICODE(N'Ɛ') -- Returns 400 DECLARE @Unicode nvarchar(11) = N'Ɛ is a char' SELECT UNICODE(@Uni...

All integers or pointers can be used in an expression that is interpreted as "truth value". int main(int argc, char* argv[]) { if (argc % 4) { puts("arguments number is not divisible by 4"); } else { puts("argument number is divisible by 4"); } ... ...

ScopedTypeVariables let you refer to universally quantified types inside of a declaration. To be more explicit: import Data.Monoid foo :: forall a b c. (Monoid b, Monoid c) => (a, b, c) -> (b, c) -> (a, b, c) foo (a, b, c) (b', c') = (a :: a, b'', c'') where (b'', c'') = (b <&g...

The code sample below shows one way to retrieve records from an MSSql Server in a background thread using FireDAC. Tested for Delphi 10 Seattle As written: The thread retrieves data using its own TFDConnection and TFDQuery and transfers the data to the form's FDQuery in a call to Sychronize...

PHP's source code is hosted on GitHub. To build from source you will first need to check out a working copy of the code. mkdir /usr/local/src/php-7.0/ cd /usr/local/src/php-7.0/ git clone -b PHP-7.0 https://github.com/php/php-src . If you want to add a feature, it's best to create your own bra...

We can use flatten() in order to lazily reduce the nesting of a multi-dimensional sequence. For example, lazy flattening a 2D array into a 1D array: // A 2D array of type [[Int]] let array2D = [[1, 3], [4], [6, 8, 10], [11]] // A FlattenBidirectionalCollection<[[Int]]> let lazilyFlatten...

Melting: The basics Melting is used to transform data from wide to long format. Starting with a wide data set: DT = data.table(ID = letters[1:3], Age = 20:22, OB_A = 1:3, OB_B = 4:6, OB_C = 7:9) We can melt our data using the melt function in data.table. This returns another data.table in long...

To use the library, you must include it as a dependency with the following line: compile project(':[library root directory]')

Methods can be defined in classes to perform a function and optionally return a result. They can receive arguments from the caller. class Something { constructor(data) { this.data = data } doSomething(text) { return { data: this.data, te...

PubNub Access Manager (PAM) extends PubNub's existing security framework by allowing developers to create and enforce secure access to channels throughout the PubNub Real Time Network. Access Manager allows you to manage granular permissions for your realtime apps and data streams, create multiple ...

fn copy_if<F>(slice: &[i32], pred: F) -> Vec<i32> where for<'a> F: Fn(&'a i32) -> bool { let mut result = vec![]; for &element in slice { if pred(&element) { result.push(element); } } result } This s...

Validate that an attribute's value matches a regular expression using format and the with option. class User < ApplicationRecord validates :name, format: { with: /\A\w{6,10}\z/ } end You can also define a constant and set its value to a regular expression and pass it to the with: option. ...

You can check if a value is included in an array using the inclusion: helper. The :in option and its alias, :within show the set of acceptable values. class Country < ApplicationRecord validates :continent, inclusion: { in: %w(Africa Antartica Asia Australia ...

That would get more control over serialization, how to save and load types Implement ISerializable interface and create an empty constructor to compile [Serializable] public class Item : ISerializable { private string _name; public string Name { get { return _name; } ...