Tutorial by Examples: d

Instance variables are unique for each instance, while class variables are shared by all instances. class C: x = 2 # class variable def __init__(self, y): self.y = y # instance variable C.x # 2 C.y # AttributeError: type object 'C' has no attribute 'y' c1 = C(3) c1....

The idea of bound and unbound methods was removed in Python 3. In Python 3 when you declare a method within a class, you are using a def keyword, thus creating a function object. This is a regular function, and the surrounding class works as its namespace. In the following example we declare method ...

Python 2.x2.2.0 New-style classes were introduced in Python 2.2 to unify classes and types. They inherit from the top-level object type. A new-style class is a user-defined type, and is very similar to built-in types. # new-style class class New(object): pass # new-style instance new = N...

In the same module Inside a module named "MyModule", Xcode generates a header named MyModule-Swift.h which exposes public Swift classes to Objective-C. Import this header in order to use the Swift classes: // MySwiftClass.swift in MyApp import Foundation // The class must be `public`...

If MyFramework contains Objective-C classes in its public headers (and the umbrella header), then import MyFramework is all that's necessary to use them from Swift. Bridging headers A bridging header makes additional Objective-C and C declarations visible to Swift code. When adding project files, ...

Supplying pow() with 3 arguments pow(a, b, c) evaluates the modular exponentiation ab mod c: pow(3, 4, 17) # 13 # equivalent unoptimized expression: 3 ** 4 % 17 # 13 # steps: 3 ** 4 # 81 81 % 17 # 13 For built-in types using modular exponentiation is only possible...

The -import-objc-header flag specifies a header for swiftc to import: // defs.h struct Color { int red, green, blue; }; #define MAX_VALUE 255 // demo.swift extension Color: CustomStringConvertible { // extension on a C struct public var description: String { return &q...

A module map can simply import mymodule by configuring it to read C header files and make them appear as Swift functions. Place a file named module.modulemap inside a directory named mymodule: Inside the module map file: // mymodule/module.modulemap module mymodule { header "defs.h&q...

public class TrustLoader { public static void main(String args[]) { try { //Gets the inputstream of a a trust store file under ssl/rpgrenadesClient.jks //This path refers to the ssl folder in the jar file, in a jar file in the same directory ...

A rebase switches the meaning of "ours" and "theirs": git checkout topic git rebase master # rebase topic branch on top of master branch Whatever HEAD's pointing to is "ours" The first thing a rebase does is resetting the HEAD to master; before cherry-picking...

Using the strtotime() function combined with date() you can parse different English text descriptions to dates: // Gets the current date echo date("m/d/Y", strtotime("now")), "\n"; // prints the current date echo date("m/d/Y", strtotime("10 September 2...

Check whether a string is empty: if str.isEmpty { // do something if the string is empty } // If the string is empty, replace it with a fallback: let result = str.isEmpty ? "fallback string" : str Check whether two strings are equal (in the sense of Unicode canonical equivale...

A Swift String is made of Unicode code points. It can be decomposed and encoded in several different ways. let str = "ที่👌①!" Decomposing Strings A string's characters are Unicode extended grapheme clusters: Array(str.characters) // ["ที่", "👌", "①", ...

The following is an example that displays 5 one-dimensional random walks of 200 steps: y = cumsum(rand(200,5) - 0.5); plot(y) legend('1', '2', '3', '4', '5') title('random walks') In the above code, y is a matrix of 5 columns, each of length 200. Since x is omitted, it defaults to the row n...

Per paragraph 6.5/5 of both C99 and C11, evaluation of an expression produces undefined behavior if the result is not a representable value of the expression's type. For arithmetic types, that's called an overflow. Unsigned integer arithmetic does not overflow because paragraph 6.2.5/9 applies, ca...

Given the following input: aaaaaAlazyZgreeedyAlaaazyZaaaaa We will use two patterns: one greedy: A.*Z, and one lazy: A.*?Z. These patterns yield the following matches: A.*Z yields 1 match: AlazyZgreeedyAlaaazyZ (examples: Regex101, Rubular) A.*?Z yields 2 matches: AlazyZ and AlaaazyZ (exampl...

Node.js can also be used to create command line utilities. The example below reads the first argument from the command line and prints a Hello message. To run this code on an Unix System: Create a new file and paste the code below. The filename is irrelevant. Make this file executable with chmo...

Using the AdvancedRTFEditorKit library you can serialize a DefaultStyledDocument to an RTF string. try { DefaultStyledDocument writeDoc = new DefaultStyledDocument(); writeDoc.insertString(0, "Test string", null); AdvancedRTFEditorKit kit = new AdvancedRTFEditorKit(); ...

This layout uses one floated column to create a two-column layout with no defined widths. In this example the left sidebar is "lazy," in that it only takes up as much space as it needs. Another way to say this is that the left sidebar is "shrink-wrapped." The right content column...

For Alerts since iOS 8, you would use a UIAlertController but for versions before, you would have used a UIAlertView, which is now deprecated. 8.0 var alert = UIAlertController.Create(title, message, UIAlertControllerStyle.Alert); alert.AddAction(UIAlertAction.Create(otherTitle, UIAlertActionStyl...