Tutorial by Examples: p

The content mode property of a view tells how its content should be laid out. In the Interface Builder, the various modes can be selected in the Attributes Inspector. Let's use two image views to see how the various modes work. Scale to Fill The image heights and widths are stretched to mat...

Create a new project It can be just a Single View Application. Add the code Create a new Cocoa Touch Class file (File > New > File... > iOS > Cocoa Touch Class). Name it MyCollectionViewCell. This class will hold the outlets for the views that you add to your cell in the storyboard. ...

The following might have undefined behavior due to incorrect pointer alignment: char *memory_block = calloc(sizeof(uint32_t) + 1, 1); uint32_t *intptr = (uint32_t*)(memory_block + 1); /* possible undefined behavior */ uint32_t mvalue = *intptr; The undefined behavior happens as the pointer...

The following code has undefined behavior: char buffer[6] = "hello"; char *ptr1 = buffer - 1; /* undefined behavior */ char *ptr2 = buffer + 5; /* OK, pointing to the '\0' inside the array */ char *ptr3 = buffer + 6; /* OK, pointing to just beyond */ char *ptr4 = buffer + 7; /* un...

An extension to PHP called Xdebug is available to assist in profiling PHP applications, as well as runtime debugging. When running the profiler, the output is written to a file in a binary format called "cachegrind". Applications are available on each platform to analyze these files. To...

Go has a built-in logging library known as log with a commonly use method Print and its variants. You can import the library then do some basic printing: package main import "log" func main() { log.Println("Hello, world!") // Prints 'Hello, world!' on a single ...

If you are inside a folder of a git repository it might be nice to show the current branch you are on. In ~/.bashrc or /etc/bashrc add the following (git is required for this to work): function prompt_command { # Check if we are inside a git repository if git status > /dev/null 2>&a...

There are many cases when one has created an NSDate from only an hour and minute format, i.e: 08:12 The downside for this situation is that your NSDate is almost completely "naked" and what you need to do is to create: day, month, year, second and time zone in order to this object to &quo...

NSAttributedString (and its mutable sibling NSMutableAttributedString) allows you to create strings that are complex in their appearance to the user. A common application is to use this to display a string and adding custom kerning / letter-spacing. This would be achieved as follows (where label ...

The package mmand provides functions for the calculation of Mathematical Morphologies for n-dimensional arrays. With a little workaround, these can also be calculated for raster images. library(raster) library(mmand) r <- raster("C:/Program Files/R/R-3.2.3/doc/html/logo.jpg") plot...

If you know the format of the string you are converting (parsing) you should use DateTime.ParseExact Dim dateString As String = "12.07.2003" Dim dateFormat As String = "dd.MM.yyyy" Dim dateValue As Date dateValue = DateTime.ParseExact(dateString, dateFormat, Globalization.C...

set myVariable [expr { $myVariable * 17 }] This shows how you can use a simple expression to update a variable. The expr command does not update the variable for you; you need to take its result and write it to the variable with set. Note that newlines are not important in the little language un...

To start, import the zipfile module, and set the filename. import zipfile filename = 'zipfile.zip' Working with zip archives is very similar to working with files, you create the object by opening the zipfile, which lets you work on it before closing the file up again. zip = zipfile.ZipFile(fi...

Typedefs are declarations which have the keyword typedef in front and before the type. E.g.: typedef int (*(*t0)())[5]; (you can technically put the typedef after the type too - like this int typedef (*(*t0)())[5]; but this is discouraged) The above declarations declares an identifier for a typ...

import scala.util.parsing.combinator._ class SimpleParser extends RegexParsers { // Define a grammar rule, turn it into a regex, and apply it the input. def word: Parser[String] = """[A-Z][a-z]+""".r ^^ { _.toString } } object SimpleParser extends SimplePar...

By default, the tooltip will appear on top of the element. We can use data-placement attribute to set the position of the tooltip on top, bottom, left or the right side of the element. <a href="#" data-toggle="tooltip" data-placement="top" title="Top tooltip&q...

Sometimes you need to call a Tcl command from your expression. For example, supposing you need the length of a string in it. To do that, you just use a [...] sequence in the expression: set halfTheStringLength [expr { [string length $theString] / 2 }] You can call any Tcl command this way, but i...

This example is based on a blog post by Nicolas Hery. It utilizes ES6 classes and ReactJS's lifecycle methods to keep the D3 component updated d3_react.html <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Hello, d3React!</title>...

CSS div { /* check remarks before usage */ height: 200px; width: 400px; background-image: url(http://lorempixel.com/400/200/nature/4); mask-image: linear-gradient(to top right, transparent 49.5%, white 50.5%), linear-gradient(to top left, transparent 49.5%, white 50.5%), linear-gradient...

When inheriting from any base class, only one partial class needs to have the base class specified. // PartialClass1.cs public partial class PartialClass : BaseClass {} // PartialClass2.cs public partial class PartialClass {} You can specify the same base class in more than one partial clas...