Tutorial by Examples: is

To generalize type_trait creation:based on SFINAE there are experimental traits detected_or, detected_t, is_detected. With template parameters typename Default, template <typename...> Op and typename ... Args: is_detected: alias of std::true_type or std::false_type depending of the validi...

Quintile analysis is a common framework for evaluating the efficacy of security factors. What is a factor A factor is a method for scoring/ranking sets of securities. For a particular point in time and for a particular set of securities, a factor can be represented as a pandas series where the in...

Calculating the factorial of a number is a classic example of a recursive function. Missing the Base Condition: #include <stdio.h> int factorial(int n) { return n * factorial(n - 1); } int main() { printf("Factorial %d = %d\n", 3, factorial(3)); return 0;...

Prior to Java 5's concurrent package introduction threading was more low level.The introduction of this package provided several higher level concurrent programming aids/constructs. Locks are thread synchronisation mechanisms that essentially serve the same purpose as synchronized blocks or key wor...

This is a mistake that causes real confusion for Java beginners, at least the first time that they do it. Instead of writing this: if (feeling == HAPPY) System.out.println("Smile"); else System.out.println("Frown"); they accidentally write this: if (feeling == HAP...

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5.6 PHP 5.6 introduced variable-length argument lists (a.k.a. varargs, variadic arguments), using the ... token before the argument name to indicate that the parameter is variadic, i.e. it is an array including all supplied parameters from that one onward. function variadic_func($nonVariadic, ...$...

C++17 A storage class specifier that hints to the compiler that a variable will be heavily used. The word "register" is related to the fact that a compiler might choose to store such a variable in a CPU register so that it can be accessed in fewer clock cycles. It was deprecated starting ...

To check if a key exists in a Map, use the .has() method: map.has(key); Example: const map = new Map([[1, 2], [3, 4]]); console.log(map.has(1)); // true console.log(map.has(2)); // false

This example is about replacing a List element while ensuring that the replacement element is at the same position as the element that is replaced. This can be done using these methods: set(int index, T type) int indexOf(T type) Consider an ArrayList containing the elements "Program sta...

Within a member function of a class, the keyword this is a pointer to the instance of the class on which the function was called. this cannot be used in a static member function. struct S { int x; S& operator=(const S& other) { x = other.x; // return a reference ...

Although package:listenv implements a list-like interface to environments, its performance relative to environments for hash-like purposes is poor on hash retrieval. However, if the indexes are numeric, it can be quite fast on retrieval. However, they have other advantages, e.g. compatibility with ...

#include <iostream> #include <string> int main() { const char * C_String = "This is a line of text w"; const char * C_Problem_String = "This is a line of text ኚ"; std::string Std_String("This is a second line of text w"); std::string...

This example consists of two parts: first, we must define our Book type; second, we use it with DynamoDBContext. [DynamoDBTable("Books")] class Book { [DynamoDBHashKey] public int Id { get; set; } public string Title { get; set; } public List<string> Authors { ...

The Collections class provides a way to make a list unmodifiable: List<String> ls = new ArrayList<String>(); List<String> unmodifiableList = Collections.unmodifiableList(ls); If you want an unmodifiable list with one item you can use: List<String> unmodifiableList = Col...

The Collections class allows for you to move objects around in the list using various methods (ls is the List): Reversing a list: Collections.reverse(ls); Rotating positions of elements in a list The rotate method requires an integer argument. This is how many spots to move it along the line b...

Suppose we have a component which will hide at a certain window width. import { Component } from '@angular/core'; @Component({ ... template: ` <div> <p [hidden]="!visible" (window:resize)="onResize($event)" >Now you see me...</p> &lt...

Starting with Java 8, you can use lambda expressions & predicates. Example: Use a lambda expressions & a predicate to get a certain value from a list. In this example every person will be printed out with the fact if they are 18 and older or not. Person Class: public class Person { p...

A DataFrame can be created from a list of dictionaries. Keys are used as column names. import pandas as pd L = [{'Name': 'John', 'Last Name': 'Smith'}, {'Name': 'Mary', 'Last Name': 'Wood'}] pd.DataFrame(L) # Output: Last Name Name # 0 Smith John # 1 Wood Mary Missin...

CREATE TYPE dbo.Ids as TABLE ( Id int PRIMARY KEY )