Tutorial by Examples: l

Multiplying a variable by 17

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...

tcl • Expressions

Opening Zip Files

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...

Python Language • Working with ZIP archives

Basic Example

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...

Scala Language • Parser Combinators

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

Positioning Tooltips

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...

twitter-bootstrap • Tooltip

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

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

Using masks to create images with irregular shapes

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...

CSS • Clipping and Masking

Partial classes inheriting from a base class

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...

C# Language • Partial class and methods

Symbolic ref names: branches, tags, remote-tracking branches

$ git log master # specify branch $ git show v1.0 # specify tag $ git show HEAD # specify current branch $ git show origin # specify default remote-tracking branch for remote 'origin' You can specify revision using a symbolic ref name, which includes branches (for example 'master'...

Git • Git revisions syntax

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 @{1} # uses reflog for current branch $ git show master@{1} # uses reflog for branch 'master' $ git show HEAD@{1} # uses 'HEAD' reflog A ref, usually a branch or HEAD, followed by the suffix @ with an ordinal specification enclosed in a brace pair (e.g. {1}, {1...

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

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

Compiling on Ubuntu

To build vim from source on Ubuntu: Get a copy of the source code by downloading from the official Vim repository on GitHub. Get the dependencies by running $ sudo apt-get build-dep vim-gnome or similar. Go to the directory of the Vim source code: cd vim/src Run $ ./configure. You can customiz...

vim • How to Compile Vim

Introduction to type-level programming

If we consider a heterogenous list, wherein the elements of the list have varied but known types, it might be desirable to be able to perform operations on the elements of the list collectively without discarding the elements' type information. The following example implements a mapping operation ov...

Scala Language • Type-level Programming

Auto-size label to fit text

This example shows how a label's width can automatically resize when the text content changes. Pin the left and top edges Just use auto layout to add constraints to pin the left and top sides of the label. After that it will automatically resize. Notes This example comes from this Stack...

iOS • UILabel

Different ways for implementing a Generic Interface (or extending a Generic Class)

Suppose the following generic interface has been declared: public interface MyGenericInterface<T> { public void foo(T t); } Below are listed the possible ways to implement it. Non-generic class implementation with a specific type Choose a specific type to replace the formal type ...

Java Language • Generics