Tutorial by Topics

Data.table is a package that extends the functionality of data frames from base R, particularly improving on their performance and syntax. See the package's Docs area at Getting started with data.table for details. DT[i, j, by] # DT[where, select|update|do, by] DT[...][...] # chaining ####...

This section provides an overview of what scheme is, and why a developer might want to use it. It should also mention any large subjects within scheme, and link out to the related topics. Since the Documentation for scheme is new, you may need to create initial versions of those related topics. ...

preg_replace($pattern, $replacement, $subject, $limit = -1, $count = 0); preg_replace_callback($pattern, $callback, $subject, $limit = -1, $count = 0); preg_match($pattern, $subject, &$matches, $flags = 0, $offset = 0); preg_match_all($pattern, $subject, &$matches, $flags = PREG_PATTERN...

This section provides an overview of what tensorflow is, and why a developer might want to use it. It should also mention any large subjects within tensorflow, and link out to the related topics. Since the Documentation for tensorflow is new, you may need to create initial versions of those rela...

React Native lets you build mobile apps using only JavaScript. It uses the same design as React, letting you compose a rich mobile UI from declarative components. With React Native, you don't build a “mobile web app”, an “HTML5 app”, or a “hybrid app”. You build a real mobile app that's indisting...

// Objective-C [UIView new] // Get a view object allocated and initialized [[UIView alloc] initWithFrame:(Pass CGRect)] // Get the view allocated and initialized with a frame [[UIView alloc] init] // Get a view object allocated and initialized // Swift UIView() // Creat...

Wild Card with % : SELECT * FROM [table] WHERE [column_name] Like '%Value%' Wild Card with _ : SELECT * FROM [table] WHERE [column_name] Like 'V_n%' Wild Card with [charlist] : SELECT * FROM [table] WHERE [column_name] Like 'V[abc]n%' LIKE condition in WHERE clause is used...

Debug.Print(string) Stop() / Stop

CMake is a tool for defining and managing code builds, primarily for C++. CMake is a cross-platform tool; the idea is to have a single definition of how the project is built - which translates into specific build definitions for any supported platform. It accomplishes this by pairing with differ...

A CSS distance measurement is a number immediately followed by a length unit (px, em, pc, in, …) CSS supports a number of length measurements units. They are absolute or relative. valueunit 1em UnitDescription%Define sizes in terms of parent objects or current object dependent on prope...

The Eloquent is an ORM (Object Relational Model) included with the Laravel. It implements the active record pattern and is used to interact with relational databases. Table naming The convention is to use pluralised “snake_case” for table names and singular “StudlyCase” for model names. For e...

INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] [INTO] tbl_name [PARTITION (partition_name,...)] [(col_name,...)] {VALUES | VALUE} ({expr | DEFAULT},...),(...),... [ ON DUPLICATE KEY UPDATE col_name=expr [, col_name=expr] ... ] INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY...

A Virtual Environment is a tool to keep the dependencies required by different projects in separate places, by creating virtual Python environments for them. It solves the “Project X depends on version 1.x but, Project Y needs 4.x” dilemma, and keeps your global site-packages directory clean and man...

DECLARE cursor_name CURSOR [ LOCAL | GLOBAL ] [ FORWARD_ONLY | SCROLL ] [ STATIC | KEYSET | DYNAMIC | FAST_FORWARD ] [ READ_ONLY | SCROLL_LOCKS | OPTIMISTIC ] [ TYPE_WARNING ] FOR select_statement [ FOR UPDATE [ OF column_name [ ,...n ] ] ] Normally you would want to avoid using...

SQLite is a relational database management system written in C. To begin working with SQLite databases within the Android framework, define a class that extends SQLiteOpenHelper, and customize as needed. The SQLiteOpenHelper class defines static onCreate() and onUpgrade() methods. These metho...

uname - to print information about your operating system. uname [OPTION]

:symbol :'symbol' :"symbol" "symbol".to_sym %s{symbol} Advantages of using symbols over strings: 1. A Ruby symbol is an object with O(1) comparison To compare two strings, we potentially need to look at every character. For two strings of length N, this will requir...