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Sending objects to a generator

In addition to receiving values from a generator, it is possible to send an object to a generator using the send() method. def accumulator(): total = 0 value = None while True: # receive sent value value = yield total if value is None: break # aggr...

Python Language • Generators

Generator expressions

It's possible to create generator iterators using a comprehension-like syntax. generator = (i * 2 for i in range(3)) next(generator) # 0 next(generator) # 2 next(generator) # 4 next(generator) # raises StopIteration If a function doesn't necessarily need to be passed a list, you can sa...

Python Language • Generators

Introduction

Generator expressions are similar to list, dictionary and set comprehensions, but are enclosed with parentheses. The parentheses do not have to be present when they are used as the sole argument for a function call. expression = (x**2 for x in range(10)) This example generates the 10 first perfe...

Python Language • Generators

External Stylesheet

An external CSS stylesheet can be applied to any number of HTML documents by placing a <link> element in each HTML document. The attribute rel of the <link> tag has to be set to "stylesheet", and the href attribute to the relative or absolute path to the stylesheet. While usin...

CSS • Getting started with CSS

Get Started

Download Xcode from the Mac App Store. Click to create a new project or playground:

Xcode • Getting started with Xcode

Getting Started

Create a new HTML file and paste the following content: <!DOCTYPE html> <html ng-app> <head> <title>Hello, Angular</title> <script src="https://code.angularjs.org/1.5.8/angular.min.js"></script> </head> <body ng-init="name=...

AngularJS • Getting started with AngularJS

Background Color

The background-color property sets the background color of an element using a color value or through keywords, such as transparent, inherit or initial. transparent, specifies that the background color should be transparent. This is default. inherit, inherits this property from its parent e...

CSS • Backgrounds

Extract the URLs and titles of links

Jsoup can be be used to easily extract all links from a webpage. In this case, we can use Jsoup to extract only specific links we want, here, ones in a h3 header on a page. We can also get the text of the links. Document doc = Jsoup.connect("http://stackoverflow.com").userAgent("Mozi...

Jsoup • Getting started with Jsoup

Addition

a, b = 1, 2 # Using the "+" operator: a + b # = 3 # Using the "in-place" "+=" operator to add and assign: a += b # a = 3 (equivalent to a = a + b) import operator # contains 2 argument arithmetic functions for the examp...

Python Language • Simple Mathematical Operators

Using CSS transform

CSS transforms are based on the size of the elements so if you don't know how tall or wide your element is, you can position it absolutely 50% from the top and left of a relative container and translate it by 50% left and upwards to center it vertically and horizontally. Keep in mind that with this...

CSS • Centering

Hello World Using Variables

Create a new file called hello.sh with the following content and give it executable permissions with chmod +x hello.sh. Execute/Run via: ./hello.sh #!/usr/bin/env bash # Note that spaces cannot be used around the `=` assignment operator whom_variable="World" # Use printf to sa...

Bash • Getting started with Bash

Subtraction

a, b = 1, 2 # Using the "-" operator: b - a # = 1 import operator # contains 2 argument arithmetic functions operator.sub(b, a) # = 1 Possible combinations (builtin types): int and int (gives an int) int and float (gives a float) int and comp...

Python Language • Simple Mathematical Operators

Getting Started

Creating a database in MySQL CREATE DATABASE mydb; Return value: Query OK, 1 row affected (0.05 sec) Using the created database mydb USE mydb; Return value: Database Changed Creating a table in MySQL CREATE TABLE mytable ( id int unsigned NOT NULL auto_increme...

MySQL • Getting started with MySQL

Multiplication

a, b = 2, 3 a * b # = 6 import operator operator.mul(a, b) # = 6 Possible combinations (builtin types): int and int (gives an int) int and float (gives a float) int and complex (gives a complex) float and float (gives a float) float and complex (gives a comple...

Python Language • Simple Mathematical Operators

Division

Python does integer division when both operands are integers. The behavior of Python's division operators have changed from Python 2.x and 3.x (see also Integer Division ). a, b, c, d, e = 3, 2, 2.0, -3, 10 Python 2.x2.7 In Python 2 the result of the ' / ' operator depends on the type of the nu...

Python Language • Simple Mathematical Operators

Exponentation

a, b = 2, 3 (a ** b) # = 8 pow(a, b) # = 8 import math math.pow(a, b) # = 8.0 (always float; does not allow complex results) import operator operator.pow(a, b) # = 8 Another difference between the built-in pow and math.pow is that the built-in po...

Python Language • Simple Mathematical Operators

Logarithms

By default, the math.log function calculates the logarithm of a number, base e. You can optionally specify a base as the second argument. import math import cmath math.log(5) # = 1.6094379124341003 # optional base argument. Default is math.e math.log(5, math.e) # = 1.6094379124341003 ...

Python Language • Simple Mathematical Operators

Rounding

Rounding Math.round() will round the value to the closest integer using half round up to break ties. var a = Math.round(2.3); // a is now 2 var b = Math.round(2.7); // b is now 3 var c = Math.round(2.5); // c is now 3 But var c = Math.round(-2.7); // c is now -3 va...

JavaScript • Arithmetic (Math)

Using a generator to find Fibonacci Numbers

A practical use case of a generator is to iterate through values of an infinite series. Here's an example of finding the first ten terms of the Fibonacci Sequence. def fib(a=0, b=1): """Generator that yields Fibonacci numbers. `a` and `b` are the seed values""" ...

Python Language • Generators