Tutorial by Examples: d

Show a git branch using PROMPT_COMMAND

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...

Bash • Customizing PS1

Convert NSDate that is composed from hour and minute (only) to a full NSDate

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...

Objective-C Language • NSDate

Converting NSDate to NSString

If ww have NSDate object, and we want to convert it into NSString. There are different types of Date strings. How we can do that?, It is very simple. Just 3 steps. Create NSDateFormatter Object NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; Set the date format in whi...

Objective-C Language • NSDate

Creating a string that has custom kerning (letter spacing) editshare

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 ...

Objective-C Language • NSAttributedString

`return` only returns from the lambda, not the outer method

The return method only returns from the lambda, not the outer method. Beware that this is different from Scala and Kotlin! void threeTimes(IntConsumer r) { for (int i = 0; i < 3; i++) { r.accept(i); } } void demo() { threeTimes(i -> { System.out.println(i); return...

Java Language • Lambda Expressions

Converting (Parsing) a String to a Date

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...

Visual Basic .NET Language • Date

Converting a Date To A String

Simply use the .ToString overload of a DateTime object to get the format you require: Dim dateValue As DateTime = New DateTime(2001, 03, 06) Dim dateString As String = dateValue.ToString("yyyy-MM-dd") '2001-03-06

Visual Basic .NET Language • Date

Introduction

Example of declarations are: int a; /* declaring single identifier of type int */ The above declaration declares single identifier named a which refers to some object with int type. int a1, b1; /* declaring 2 identifiers of type int */ The second declaration declares 2 identifiers named a1 a...

C Language • Declarations

Typedef

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...

C Language • Declarations

Renaming all files in the current directory

The following uses a variable with a for loop to rename a group of files. SetLocal EnableDelayedExpansion for %%j in (*.*) do ( set filename=%%~nj set filename=!filename:old=new! set filename=Prefix !filename! set filename=!filename! Suffix ren "%%j" "!filename!%%~x...

batch-file • For Loops in Batch Files

Calling a Tcl command from an expression

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...

tcl • Expressions

Hello, world!

Create an .html file containing this snippet: <!DOCTYPE html> <meta charset="utf-8"> <body> <script src="//d3js.org/d3.v4.min.js"></script> <script> d3.select("body").append("span") .text("Hello, world!&quo...

d3.js • Getting started with d3.js

D3.js component with ReactJS

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>...

d3.js • Using D3 with other frameworks

Using masks to cut a hole in the middle of an image

CSS div { width: 200px; height: 200px; background: url(http://lorempixel.com/200/200/abstract/6); mask-image: radial-gradient(circle farthest-side at center, transparent 49%, white 50%); /* check remarks before using */ } HTML In the above example, a transparent circle is created...

CSS • Clipping and Masking

The default revision: HEAD

$ git show # equivalent to 'git show HEAD' 'HEAD' names the commit on which you based the changes in the working tree, and is usually the symbolic name for the current branch. Many (but not all) commands that take revision parameter defaults to 'HEAD' if it is missing.

Git • Git revisions syntax

Reflog references: @{}

$ git show master@{yesterday} $ git show HEAD@{5 minutes ago} # or HEAD@{5.minutes.ago} A ref followed by the suffix @ with a date specification enclosed in a brace pair (e.g. {yesterday}, {1 month 2 weeks 3 days 1 hour 1 second ago} or {1979-02-26 18:30:00}) specifies the value of the ref at ...

Git • Git revisions syntax

Tracked / upstream branch: @{upstream}

$ git log @{upstream}.. # what was done locally and not yet published, current branch $ git show master@{upstream} # show upstream of branch 'master' The suffix @{upstream} appended to a branchname (short form <branchname>@{u}) refers to the branch that the branch specified by branc...

Git • Git revisions syntax

Dereferencing branches and tags: ^0, ^{}

In some cases the behavior of a command depends on whether it is given branch name, tag name, or an arbitrary revision. You can use "de-referencing" syntax if you need the latter. A suffix ^ followed by an object type name (tag, commit, tree, blob) enclosed in brace pair (for example v0.9...

Git • Git revisions syntax

Code Folding Preferences

It is possible to change Code Folding preference to suit your need. Thus code folding can be set enable/unable for specific constructs (ex: if block, for loop, Sections ...). To change folding preferences, go to Preferences -> Code Folding: Then you can choose which part of the code can be f...

MATLAB Language • Useful tricks

Directly including JavaScript code

Instead of linking to an external file, you can also include the JS code as-is in your HTML: <script> // JavaScript code </script>

HTML • Include JavaScript Code in HTML