book

Learning R Programming

Name: Learning R Programming
Author: Kun Ren
ISBN: 9781785889776

by Kun Ren

October 2016

Beginner to intermediate

582 pages

11h 26m

English

Packt Publishing

Read now

Unlock full access

Learning R Programming
Learning R Programming
Credits
About the Author
About the Reviewer
www.PacktPub.com
Why subscribe?
Preface
What this book covers
What you need for this book
Who this book is for
Conventions

Reader feedback
Customer support
Downloading the example codeErrataPiracyQuestions
1. Quick Start
Introducing RR as a programming languageR as a computing environmentR as a communityR as an ecosystem
The need for R
Installing R
RStudio
RStudio's user interfaceThe consoleThe editorThe Environment paneThe History paneThe File paneThe Plots paneThe Packages paneThe Help paneThe Viewer paneRStudio Server
A quick example
Summary
2. Basic Objects
VectorNumeric vectorLogical vectorCharacter vectorSubsetting vectorsNamed vectorsExtracting an elementTelling the class of vectorsConverting vectorsArithmetic operators for numeric vectors
Matrix
Creating a matrixNaming rows and columnsSubsetting a matrixUsing matrix operators
Array
Creating an arraySubsetting an array
Lists
Creating a listExtracting an element from a listSubsetting a listNamed listsSetting valuesOther functions
Data frames
Creating a data frameNaming rows and columnsSubsetting a data frameSubsetting a data frame as a listSubsetting a data frame as a matrixFiltering dataSetting valuesSetting values as a listSetting values as a matrixFactorsUseful functions for data framesLoading and writing data on disk
Functions
Creating a functionCalling a functionDynamic typingGeneralizing a functionDefault value for function arguments
Summary
3. Managing Your Workspace
R's working directoryCreating an R project in RStudioComparing absolute and relative pathsManaging project files
Inspecting the environment
Inspecting existing symbolsViewing the structure of an objectRemoving symbols
Modifying global options
Modifying the number of digits to printModifying the warning level
Managing the library of packages
Getting to know a packageInstalling packages from CRANUpdating packages from CRANInstalling packages from online repositoriesUsing package functionsMasking and name conflictsChecking whether a package is installed
Summary
4. Basic Expressions
Assignment expressionsAlternative assignment operatorsUsing backticks with non-standard names
Conditional expressions
Using if as a statementUsing if as an expressionUsing if with vectorsUsing vectorized if: ifelseUsing switch to branch values
Loop expressions
Using the for loopManaging the flow of a for loopCreating nested for loopsUsing the while loop
Summary
5. Working with Basic Objects
Using object functionsTesting object typesAccessing object classes and typesAccessing data dimensionsGetting data dimensionsReshaping data structuresIterating over one dimension
Using logical functions
Logical operatorsLogical functionsAggregating logical vectorsAsking which elements are TRUEDealing with missing valuesLogical coercion
Using math functions
Basic functionsNumber rounding functionsTrigonometric functionsHyperbolic functionsExtreme functions
Applying numeric methods
Root findingCalculusDerivativesIntegration
Using statistical functions
Sampling from a vectorWorking with random distributionsComputing summary statisticsComputing covariance and correlation matrix
Using apply-family functions
lapplysapplyvapplymapplyapply
Summary
6. Working with Strings
Getting started with stringsPrinting textsConcatenating stringsTransforming textsChanging casesCounting charactersTrimming leading and trailing whitespacesSubstringSplitting textsFormatting textsUsing Python string functions in R
Formatting date/time
Parsing text as date/timeFormatting date/time to strings
Using regular expressions
Finding a string patternUsing groups to extract the dataReading data in customizable ways
Summary
7. Working with Data
Reading and writing dataReading and writing text-format data in a fileImporting data via RStudio IDEImporting data using built-in functionsImporting data using the readr packageWriting a data frame to a fileReading and writing Excel worksheetsReading and writing native data filesReading and writing a single object in native formatSaving and restoring the working environmentLoading built-in datasets
Visualizing data
Creating scatter plotsCustomizing chart elementsCustomizing point stylesCustomizing point colorsCreating line plotsCustomizing line type and widthPlotting lines in multiple periodsPlotting lines with pointsPlotting a multi-series chart with a legendCreating bar chartsCreating pie chartsCreating histogram and density plotsCreating box plots
Analyzing data
Fitting a linear modelFitting a regression tree
Summary
8. Inside R
Understanding lazy evaluation
Understanding the copy-on-modify mechanism
Modifying objects outside a function
Understanding lexical scoping
Understanding how an environment works
Knowing the environment objectCreating and chaining environmentsAccessing an environmentChaining environmentsUsing environments for reference semanticsKnowing the built-in environmentsUnderstanding environments associated with a function
Summary
9. Metaprogramming
Understanding functional programmingCreating and using closuresCreating a simple closureMaking specialized functionsFitting normal distribution with maximal likelihood estimationUsing higher-order functionsCreating aliases for functionsUsing functions as variablesPassing functions as arguments
Computing on language
Capturing and modifying expressionsCapturing expressions as language objectsModifying expressionsCapturing expressions of function argumentsConstructing function callsEvaluating expressionsUnderstanding non-standard evaluationImplementing quick subsetting using non-standard evaluationUnderstanding dynamic scopingUsing formulas to capture expression and environmentImplementing subset with metaprogramming
Summary
10. Object-Oriented Programming
Introducing object-oriented programmingUnderstanding classes and methodsUnderstanding inheritance
Working with the S3 object system
Understanding generic functions and method dispatchWorking with built-in classes and methodsDefining generic functions for existing classesCreating objects of new classesUsing list as the underlying data structureUsing an atomic vector as the underlying data structureUnderstanding S3 inheritance
Working with S4
Defining S4 classesUnderstanding S4 inheritanceDefining S4 generic functionsUnderstanding multiple dispatch
Working with the reference class
Working with R6
Summary
11. Working with Databases
Working with relational databasesCreating a SQLite databaseWriting multiple tables to a databaseAppending data to a tableAccessing tables and table fieldsLearning SQL to query relational databasesFetching query results chunk by chunkUsing transactions for consistencyStoring data in files to a database
Working with NoSQL databases
Working with MongoDBQuerying data from MongoDBCreating and removing indexesUsing RedisAccessing Redis from RSetting and getting values from the Redis server
Summary
12. Data Manipulation
Using built-in functions to manipulate data framesUsing built-in functions to manipulate data framesReshaping data frames using reshape2
Using SQL to query data frames via the sqldf package
Using data.table to manipulate data
Using key to access rowsSummarizing data by groupsReshaping data.tableUsing in-place set functionsUnderstanding dynamic scoping of data.table
Using dplyr pipelines to manipulate data frames
Using rlist to work with nested data structures
Summary
13. High-Performance Computing
Understanding code performance issuesMeasuring code performance
Profiling code
Profiling code with RprofProfiling code with profvisUnderstanding why code can be slow
Boosting code performance
Using built-in functionsUsing vectorizationUsing byte-code compilerUsing Intel MKL-powered R distributionUsing parallel computingUsing parallel computing on WindowsUsing parallel computing on Linux and MacOSUsing RcppOpenMPRcppParallel
Summary
14. Web Scraping
Looking inside web pages
Extracting data from web pages using CSS selectors
Learning XPath selectors
Analysing HTML code and extracting data
Summary
15. Boosting Productivity
Writing R Markdown documentsGetting to know markdownIntegrating R into MarkdownEmbedding tables and chartsEmbedding tablesEmbedding charts and diagramsEmbedding interactive plots
Creating interactive apps
Creating a shiny appUsing shinydashboard
Summary

Content preview from Learning R Programming

Chapter 4. Basic Expressions

Expressions are the building blocks of a function. R has a very clear syntax that suggests that an expression is either a symbol or a function call.

Although everything we do is in essence implemented by functions, R gives some functions a special syntax so that it is more friendly to write readable R code.

In the next few sections, we will see the following fundamental expressions that are given a special syntax:

Assignment expressions
Conditional expressions
Loop expressions

Assignment expressions

Assignment may be one of the most fundamental expressions in all programming languages. What it does is assign or bind a value to a symbol so that we can refer to the value by that symbol later.

Despite the similarity, R adopts ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.

Julian F.

Head of Cybersecurity

I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.

Addison B.

Field Engineer

I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.

Amir M.

Data Platform Tech Lead

I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.

Mark W.

Embedded Software Engineer

Publisher Resources

ISBN: 9781785889776

Cloud Computing

Data Engineering

Data Science

AI & ML

Programming Languages

Software Architecture

IT/Ops

Security

Design

Business

Soft Skills

Learning R Programming

by Kun Ren

Chapter 4. Basic Expressions

Assignment expressions

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.