Tutorial by Examples: ti

By default, a Date object is created as local time. This is not always desirable, for example when communicating a date between a server and a client that do not reside in the same timezone. In this scenario, one doesn't want to worry about timezones at all until the date needs to be displayed in lo...

A very simple way to import data from many common file formats is with rio. This package provides a function import() that wraps many commonly used data import functions, thereby providing a standard interface. It works simply by passing a file name or URL to import(): import("example.csv&quot...

Final classes When used in a class declaration, the final modifier prevents other classes from being declared that extend the class. A final class is a "leaf" class in the inheritance class hierarchy. // This declares a final class final class MyFinalClass { /* some code */ } ...

The and-operator (&&) and the or-operator (||) employ short-circuiting to prevent unnecessary work if the outcome of the operation does not change with the extra work. In x && y, y will not be evaluated if x evaluates to false, because the whole expression is guaranteed to be false....

You will first need to create a directory, access it in your shell and install Express using npm by running npm install express --save Create a file and name it app.js and add the following code which creates a new Express server and adds one endpoint to it (/ping) with the app.get method: const e...

A dictionary is an example of a key value store also known as Mapping in Python. It allows you to store and retrieve elements by referencing a key. As dictionaries are referenced by key, they have very fast lookups. As they are primarily used for referencing items by key, they are not sorted. crea...

Python 3.2+ has support for %z format when parsing a string into a datetime object. UTC offset in the form +HHMM or -HHMM (empty string if the object is naive). Python 3.x3.2 import datetime dt = datetime.datetime.strptime("2016-04-15T08:27:18-0500", "%Y-%m-%dT%H:%M:%S%z"...

Dates don't exist in isolation. It is common that you will need to find the amount of time between dates or determine what the date will be tomorrow. This can be accomplished using timedelta objects import datetime today = datetime.date.today() print('Today:', today) yesterday = today - date...

The $_SESSION variable is an array, and you can retrieve or manipulate it like a normal array. <?php // Starting the session session_start(); // Storing the value in session $_SESSION['id'] = 342; // conditional usage of session values that may have been set in a previous session if(!i...

Use std::string::substr to split a string. There are two variants of this member function. The first takes a starting position from which the returned substring should begin. The starting position must be valid in the range (0, str.length()]: std::string str = "Hello foo, bar and world!"...

You can concatenate std::strings using the overloaded + and += operators. Using the + operator: std::string hello = "Hello"; std::string world = "world"; std::string helloworld = hello + world; // "Helloworld" Using the += operator: std::string hello = "Hel...

var fs = require('fs'); // Save the string "Hello world!" in a file called "hello.txt" in // the directory "/tmp" using the default encoding (utf8). // This operation will be completed in background and the callback // will be called when it is either done or fail...

const fs = require('fs'); // Read the contents of the directory /usr/local/bin asynchronously. // The callback will be invoked once the operation has either completed // or failed. fs.readdir('/usr/local/bin', (err, files) => { // On error, show it and return if(err) return console.er...

Use Case CASE can be used in conjunction with SUM to return a count of only those items matching a pre-defined condition. (This is similar to COUNTIF in Excel.) The trick is to return binary results indicating matches, so the "1"s returned for matching entries can be summed for a count o...

in myapp/context_processors.py: from django.conf import settings def debug(request): return {'DEBUG': settings.DEBUG} in settings.py: TEMPLATES = [ { ... 'OPTIONS': { 'context_processors': [ ... 'myapp.context_processor...

project/jni/main.c #include <stdio.h> #include <unistd.h> int main(void) { printf("Hello world!\n"); return 0; } project/jni/Android.mk LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := hello_world LOCAL_SRC_FILES := main.c include $(BU...

Sometimes you have a module that you only want to import so its top-level code gets run. This is useful for polyfills, other globals, or configuration that only runs once when your module is imported. Given a file named test.js: console.log('Initializing...') You can use it like this: import '...

Given that the module from the Defining a Module section exists in the file test.js, you can import from that module and use its exported members: import {doSomething, MyClass, PI} from './test' doSomething() const mine = new MyClass() mine.test() console.log(PI) The somethingPrivate()...

The keyword 'using' has three flavors. Combined with keyword 'namespace' you write a 'using directive': If you don't want to write Foo:: in front of every stuff in the namespace Foo, you can use using namespace Foo; to import every single thing out of Foo. namespace Foo { void bar() {} ...

There are several ways to write to a file. The easiest way is to use an output file stream (ofstream) together with the stream insertion operator (<<): std::ofstream os("foo.txt"); if(os.is_open()){ os << "Hello World!"; } Instead of <<, you can also ...