Tutorial by Examples: le

To check if an element with a specified key exits in a WeakMap, use the .has() method. It returns true if it exits, and otherwise false. const obj1 = {}, obj2 = {}; const weakmap = new WeakMap([[obj1, 7]]); console.log(weakmap.has(obj1)); // true console.log(weakmap.has(obj2)); // false...

To remove an element with a specified key, use the .delete() method. It returns true if the element existed and has been removed, otherwise false. const obj1 = {}, obj2 = {}; const weakmap = new WeakMap([[obj1, 7]]); console.log(weakmap.delete(obj1)); // true console.log(weakmap.has(obj...

In order to compile docker its recommended you have at least 2 GB RAM. Even with that it fails sometimes so its better to go for 4GB instead. make sure git and make is installed sudo apt-get install make git-core -y install a new kernel (at least 4.2) sudo apt-get install linux-generic...

-- Create demo database CREATE DATABASE SQL2016_Demo ON PRIMARY ( NAME = N'SQL2016_Demo', FILENAME = N'C:\Dump\SQL2016_Demo.mdf', SIZE = 5120KB, FILEGROWTH = 1024KB ) LOG ON ( NAME = N'SQL2016_Demo_log', FILENAME = N'C:\Dump\SQL2016_Demo_log.ldf', ...

SELECT OBJECT_ID('MemOptTable1') AS MemOptTable1_ObjectID, OBJECT_ID('MemOptTable2') AS MemOptTable2_ObjectID GO SELECT name,description FROM sys.dm_os_loaded_modules WHERE name LIKE '%XTP%' GO Show all Memory Optimized Tables: SELECT name,type_desc,durability_desc,...

For example, this is traditional tempdb-based table type: CREATE TYPE dbo.testTableType AS TABLE ( col1 INT NOT NULL, col2 CHAR(10) ); To memory-optimize this table type simply add the option memory_optimized=on, and add an index if there is none on the original type: CREATE TYPE dbo....

For faster performance you can memory-optimize your table variable. Here is the T-SQL for a traditional table variable: DECLARE @tvp TABLE ( col1 INT NOT NULL , Col2 CHAR(10) ); To define memory-optimized variables, you must first create a memory-optimized table type and...

Recommendation Because the symbols i and j can represent significantly different things in MATLAB, their use as loop indices has split the MATLAB user community since ages. While some historic performance reasons could help the balance lean to one side, this is no longer the case and now the choice...

CREATE TABLE dbo.Employee ( [EmployeeID] int NOT NULL PRIMARY KEY CLUSTERED , [Name] nvarchar(100) NOT NULL , [Position] varchar(100) NOT NULL , [Department] varchar(100) NOT NULL , [Address] nvarchar(1024) NOT NULL , [AnnualSalary] decimal (10,2) NOT NULL ...

Required compiler features can be specified on a target using the command target_compile_features: add_library(foo foo.cpp ) target_compile_features(foo PRIVATE # scope of the feature cxx_constexpr # list of features ) The features must be part of CMAKE_C_COMPILE_FE...

MailApp is the api from Google App Script that can be used to send mail function sendEmails() { var subject = "A subject for your new app!"; var message = "And this is the very first message" var recipientEmail = "[email protected]"; MailApp.sendEmail(rec...

Design (layout XML): <AutoCompleteTextView android:id="@+id/autoCompleteTextView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_centerHorizontal="true&...

This example shows the base of almost any XSLT transformation and the most fundamental XSLT design pattern. Producing as output an XML document that is identical to the source XML document. Source XML document: <t>Hello, World!</t> XSLT transformation: <xsl:stylesheet version=&q...

A downcast can be used to make use of a subclass's code and data inside of a function taking a parameter of its superclass. class Rat { var color = "white" } class PetRat: Rat { var name = "Spot" } func nameOfRat(🐭: Rat) -> String { guard let petRat = ...

In the following code let us assume for simplicity that float and uint32_t have the same size. void fun(uint32_t* u, float* f) { float a = *f *u = 22; float b = *f; print("%g should equal %g\n", a, b); } u and f have different base type, and thus the compiler can a...

Copy byte-per-byte of a file The following function copies a file into another by performing an exact byte-per-byte copy, ignoring the kind of content (which can be either lines of characters in some encoding or binary data): (defun byte-copy (infile outfile) (with-open-file (instream infile :d...

null returns True if there are no elements a in a foldable structure t a, and False if there is one or more. Structures for which null is True have a length of 0. ghci> null [] True ghci> null [14, 29] False ghci> null Nothing True ghci> null (Right 'a') False ghci> null ('x'...

The loop macro supports iteration over the keys, the values, or the keys and values of a hash table. The following examples show possibilities, but the full loop syntax allows more combinations and variants. Over keys and values (let ((ht (make-hash-table))) (setf (gethash 'a ht) 1 (g...

The keys and values of a hash table can be iterated over using the macro with-hash-table-iterator. This may be a bit more complex than maphash or loop, but it could be used to implement the iteration constructs used in those methods. with-hash-table-iterator takes a name and a hash table and binds...

In fluent programming style you return this from fluent (setter) methods that would return nothing in non-fluent programming style. This allows you to chain the different method calls which makes your code shorter and easier to handle for the developers. Consider this non-fluent code: public clas...