Tutorial by Examples: re

$url = "https://api.dropboxapi.com/2/users/get_current_account" $req = [System.Net.HttpWebRequest]::Create($url) $req.headers["Authorization"] = "Bearer <ACCESS_TOKEN>" $req.Method = "POST" $res = $req.GetResponse() Write-Host "Response Sta...

Consider the below list comprehension: >>> def f(x): ... import time ... time.sleep(.1) # Simulate expensive function ... return x**2 >>> [f(x) for x in range(1000) if f(x) > 10] [16, 25, 36, ...] This results in two calls to f(x) for 1,000 values of...

To create a new Date object use the Date() constructor: with no arguments Date() creates a Date instance containing the current time (up to milliseconds) and date. with one integer argument Date(m) creates a Date instance containing the time and date corresponding to the Epoch time (...

In this example, we're going to set up an Express server integration to display how to process a payment with PayPal, using the PayPal Node SDK. We will use a static JSON structure for the payment details for the sake of brevity. There are three general steps that we will follow when building out t...

git ls-remote is one unique command allowing you to query a remote repo without having to clone/fetch it first. It will list refs/heads and refs/tags of said remote repo. You will see sometimes refs/tags/v0.1.6 and refs/tags/v0.1.6^{}: the ^{} to list the dereferenced annotated tag (ie the commit ...

If you need to use the ^ character in a character class (Character classes ), either put it somewhere other than the beginning of the class: [12^3] Or escape the ^ using a backslash \: [\^123] If you want to match the caret character itself outside a character class, you need to escape it: ...

To conditionally include a block of code, the preprocessor has several directives (e.g #if, #ifdef, #else, #endif, etc). /* Defines a conditional `printf` macro, which only prints if `DEBUG` * has been defined */ #ifdef DEBUG #define DLOG(x) (printf(x)) #else #define DLOG(x) #endif Norm...

The simplest form of macro replacement is to define a manifest constant, as in #define ARRSIZE 100 int array[ARRSIZE]; This defines a function-like macro that multiplies a variable by 10 and stores the new value: #define TIMES10(A) ((A) *= 10) double b = 34; int c = 23; TIMES10(b); //...

If the preprocessor encounters an #error directive, compilation is halted and the diagnostic message included is printed. #define DEBUG #ifdef DEBUG #error "Debug Builds Not Supported" #endif int main(void) { return 0; } Possible output: $ gcc error.c error.c: error: #e...

The searched CASE returns results when a boolean expression is TRUE. (This differs from the simple case, which can only check for equivalency with an input.) SELECT Id, ItemId, Price, CASE WHEN Price < 10 THEN 'CHEAP' WHEN Price < 20 THEN 'AFFORDABLE' ELSE 'EXPENSIVE' E...

Indexes can have several characteristics that can be set either at creation, or by altering existing indexes. CREATE CLUSTERED INDEX ix_clust_employee_id ON Employees(EmployeeId, Email); The above SQL statement creates a new clustered index on Employees. Clustered indexes are indexes that dict...

Classes are reference types, meaning that multiple variables can refer to the same instance. class Dog { var name = "" } let firstDog = Dog() firstDog.name = "Fido" let otherDog = firstDog // otherDog points to the same Dog instance otherDog.name = "Rover" // modifying otherDog also...

The Implicit Grant flow is best suited for Web applications. It's easily integrated into a website using JavaScript and doesn't require a server to store the authorization code to retrieve a token. You'll first send the user to the Twitch authorization endpoint. This URL is made up of a the base au...

The second step to creating a subscription for a user is to create and execute a billing agreement, based on an existing activated billing plan. This example assumes that you have already gone through and activated a billing plan in the previous example, and have an ID for that billing plan to refer...

When creating a subscription for a user, you first need to create and activate a billing plan that a user is then subscribed to using a billing agreement. The full process for creating a subscription is detailed in the remarks of this topic. Within this example, we're going to be using the PayPal N...

HTML comments can be used to leave notes to yourself or other developers about a specific point in code. They can be initiated with <!-- and concluded with -->, like so: <!-- I'm an HTML comment! --> They can be incorporated inline within other content: <h1>This part will be d...

Conditional comments can be used to customize code for different versions of Microsoft Internet Explorer. For example, different HTML classes, script tags, or stylesheets can be provided. Conditional comments are supported in Internet Explorer versions 5 through 9. Older and newer Internet Explorer ...

Basic implementation: <script src= "http://player.twitch.tv/js/embed/v1.js"></script> <div id="PLAYER_DIV_ID"></div> <script type="text/javascript"> var options = { width: 854, height: 480, channel: "...

$.ajax({ url: 'https://api.dropboxapi.com/2/sharing/add_folder_member', type: 'POST', processData: false, data: JSON.stringify({"shared_folder_id": "84528192421","members": [{"member": {".tag": "email","email":...

Optionals must be unwrapped before they can be used in most expressions. if let is an optional binding, which succeeds if the optional value was not nil: let num: Int? = 10 // or: let num: Int? = nil if let unwrappedNum = num { // num has type Int?; unwrappedNum has type Int print(&quo...