Tutorial by Examples: g

Lambda functions in C++ are syntactic sugar that provide a very concise syntax for writing functors. As such, equivalent functionality can be obtained in C++03 (albeit much more verbose) by converting the lambda function into a functor: // Some dummy types: struct T1 {int dummy;}; struct T2 {int ...

This example assumes you know how to test a Flask app using pytest Below is an API that takes a JSON input with integer values a and b e.g. {"a": 1, "b": 2}, adds them up and returns sum a + b in a JSON response e.g. {"sum": 3}. # hello_add.py from flask import Flask...

Generics are placeholders for types, allowing you to write flexible code that can be applied across multiple types. The advantage of using generics over Any is that they still allow the compiler to enforce strong type-safety. A generic placeholder is defined within angle brackets <>. Generic...

cURL is a tool for transferring data with URL syntax. It support HTTP, FTP, SCP and many others(curl >= 7.19.4). Remember, you need to install and enable the cURL extension to use it. // a little script check is the cURL extension loaded or not if(!extension_loaded("curl")) { die...

The two parameters to Range are the first number and the count of elements to produce (not the last number). // prints 1,2,3,4,5,6,7,8,9,10 Console.WriteLine(string.Join(",", Enumerable.Range(1, 10))); // prints 10,11,12,13,14 Console.WriteLine(string.Join(",", Enumerable.R...

Due to Node's asynchronous nature, creating or using a directory by first: checking for its existence with fs.stat(), then creating or using it depending of the results of the existence check, can lead to a race condition if the folder is created between the time of the check and the time of ...

In Android, a Toast is a simple UI element that can be used to give contextual feedback to a user. To display a simple Toast message, we can do the following. // Declare the parameters to use for the Toast Context context = getApplicationContext(); // in an Activity, you may also use "th...

If you don't want to use the default Toast view, you can provide your own using the setView(View) method on a Toast object. First, create the XML layout you would like to use in your Toast. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="...

cursor: value; Examples: ValueDescriptionnoneNo cursor is rendered for the elementautoDefault. The browser sets a cursorhelpThe cursor indicates that help is availablewaitThe cursor indicates that the program is busymoveThe cursor indicates something is to be movedpointerThe cursor is a pointe...

The nodemon package makes it possible to automatically reload your program when you modify any file in the source code. Installing nodemon globally npm install -g nodemon (or npm i -g nodemon) Installing nodemon locally In case you don't want to install it globally npm install --save-dev nodemo...

In $e:expr, the expr is called the fragment specifier. It tells the parser what kind of tokens the parameter $e is expecting. Rust provides a variety of fragment specifiers to, allowing the input to be very flexible. SpecifierDescriptionExamplesidentIdentifierx, foopathQualified namestd::collection...

Exporting a macro to allow other modules to use it: #[macro_export] // ^~~~~~~~~~~~~~~ Think of it as `pub` for macros. macro_rules! my_macro { (..) => {..} } Using macros from other crates or modules: #[macro_use] extern crate lazy_static; // ^~~~~~~~~~~~ Must add this in ord...

(All of these are unstable, and thus can only be used from a nightly compiler.) log_syntax!() #![feature(log_syntax)] macro_rules! logged_sum { ($base:expr) => { { log_syntax!(base = $base); $base } }; ($a:expr, $($rest:expr),+) => { { log_syntax!(a = $...

docker inspect supports Go Templates via the --format option. This allows for better integration in scripts, without resorting to pipes/sed/grep traditional tools. Print a container internal IP: docker inspect --format '{{ .NetworkSettings.IPAddress }}' 7786807d8084 This is useful for direct ne...

extern crate serde; extern crate serde_json; macro_rules! enum_str { ($name:ident { $($variant:ident($str:expr), )* }) => { #[derive(Clone, Copy, Debug, Eq, PartialEq)] pub enum $name { $($variant,)* } impl ::serde::Serialize for $name {...

Say we have an enum DayOfWeek: enum DayOfWeek { SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY; } An enum is compiled with a built-in static valueOf() method which can be used to lookup a constant by its name: String dayName = DayOfWeek.SUNDAY.name(); assert dayName.equal...

This topic specifically talks about UTF-8 and considerations for using it with a database. If you want more information about using databases in PHP then checkout this topic. Storing Data in a MySQL Database: Specify the utf8mb4 character set on all tables and text columns in your database. ...

JSFiddle: https://jsfiddle.net/UnsungHero97/80qod7aL/2/ HTML <div class="box_shadow"></div> CSS .box_shadow { background-color: #1C90F3; width: 200px; height: 100px; margin: 50px; } .box_shadow:after { content: ""; width: 190px; height: ...

If you need to match characters that are a part of the regular expression syntax you can mark all or part of the pattern as a regex literal. \Q marks the beginning of the regex literal. \E marks the end of the regex literal. // the following throws a PatternSyntaxException because of the un-close...

The following code will print the arguments to the program, and the code will attempt to convert each argument into a number (to a long): #include <stdlib.h> #include <stdio.h> #include <errno.h> #include <limits.h> int main(int argc, char* argv[]) { for (int ...