Tutorial by Examples: r

/* * The built-in (previously called default) VCL code. * * NB! You do NOT need to copy & paste all of these functions into your * own vcl code, if you do not provide a definition of one of these * functions, the compiler will automatically fall back to the default * code from this f...

Generators are functions which are able to pause and then resume execution. This allows to emulate async functions using external libraries, mainly q or co. Basically it allows to write functions that wait for async results in order to go on: function someAsyncResult() { return Promise.resolve...

Stream operations fall into two main categories, intermediate and terminal operations, and two sub-categories, stateless and stateful. Intermediate Operations: An intermediate operation is always lazy, such as a simple Stream.map. It is not invoked until the stream is actually consumed. This can...

Insert a document called 'myFirstDocument' and set 2 properties, greetings and farewell const MongoClient = require('mongodb').MongoClient; const url = 'mongodb://localhost:27017/test'; MongoClient.connect(url, function (err, db) { if (err) throw new Error(err); db.collection('myCollect...

Get all documents in the collection 'myCollection' and print them to the console. const MongoClient = require('mongodb').MongoClient; const url = 'mongodb://localhost:27017/test'; MongoClient.connect(url, function (err, db) { if (err) throw new Error(err); var cursor = db.collection('my...

You can use the plus (+) operator to concatenate strings: 'Dart ' + 'is ' + 'fun!'; // 'Dart is fun!' You can also use adjacent string literals for concatenation: 'Dart ' 'is ' 'fun!'; // 'Dart is fun!' You can use ${} to interpolate the value of Dart expressions within strings. The curly...

A string can be either single or multiline. Single line strings are written using matching single or double quotes, and multiline strings are written using triple quotes. The following are all valid Dart strings: 'Single quotes'; "Double quotes"; 'Double quotes in "single" quo...

Programmatically generating a String is best accomplished with a StringBuffer. A StringBuffer doesn't generate a new String object until toString() is called. var sb = new StringBuffer(); sb.write("Use a StringBuffer"); sb.writeAll(["for ", "efficient ", "stri...

for arg; do echo arg=$arg done A for loop without a list of words parameter will iterate over the positional parameters instead. In other words, the above example is equivalent to this code: for arg in "$@"; do echo arg=$arg done In other words, if you catch yourself wri...

An array is a stack-allocated, statically-sized list of objects of a single type. Arrays are usually created by enclosing a list of elements of a given type between square brackets. The type of an array is denoted with the special syntax: [T; N] where T is the type of its elements and N their count...

# The following shell function will be used to generate completions for # the "nuance_tune" command. _nuance_tune_opts () { local curr_arg prev_arg curr_arg=${COMP_WORDS[COMP_CWORD]} prev_arg=${COMP_WORDS[COMP_CWORD-1]} # The "config" option takes a file arg, so ...

If we want to order the data differently for per group, we can add a CASE syntax to the ORDER BY. In this example, we want to order employees from Department 1 by last name and employees from Department 2 by salary. IdFNameLNamePhoneNumberManagerIdDepartmentIdSalaryHireDate1JamesSmith1234567890NUL...

We are so used to the name D3.js that it's possible to forget that D3 is actually DDD (Data-Driven Documents). And that's what D3 does well, a data-driven approach to DOM (Document Object Model) manipulation: D3 binds data to DOM elements and manipulates those elements based on the bounded data. Le...

git log --pretty=format:"%Cgreen%ci %Cblue%cn %Cgreen%cr%Creset %s" This will give a nice overview of all commits (1 per line) with date, user and commit message. The --pretty option has many placeholders, each starting with %. All options can be found here

It is not possible to add and commit an empty folder in Git due to the fact that Git manages files and attaches their directory to them, which slims down commits and improves speed. To get around this, there are two methods: Method one: .gitkeep One hack to get around this is to use a .gitkeep fil...

Arrow functions do not expose an arguments object; therefore, arguments would simply refer to a variable in the current scope. const arguments = [true]; const foo = x => console.log(arguments[0]); foo(false); // -> true Due to this, arrow functions are also not aware of their caller/ca...

Arrow functions may implicitly return values by simply omitting the curly braces that traditionally wrap a function's body if their body only contains a single expression. const foo = x => x + 1; foo(1); // -> 2 When using implicit returns, object literals must be wrapped in parenthesis s...

Arrow functions can behave very similar to classic functions in that you may explicitly return a value from them using the return keyword; simply wrap your function's body in curly braces, and return a value: const foo = x => { return x + 1; } foo(1); // -> 2

xcrun uses the system default Xcode version (set via xcode-select) to locate and execute command line tools from the Xcode application bundle, e.g., llvm-cov. # Generate code coverage reports via llvm-cov # /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin xc...

C extensions are comprised of two general pieces: The C Code itself. The extension configuration file. To get started with your first extension put the following in a file named extconf.rb: require 'mkmf' create_makefile('hello_c') A couple of things to point out: First, the name hell...