{"id":9060,"date":"2012-10-15T10:46:59","date_gmt":"2012-10-15T09:46:59","guid":{"rendered":"https:\/\/www.portfolioprobe.com\/?p=9060"},"modified":"2012-10-16T10:20:16","modified_gmt":"2012-10-16T09:20:16","slug":"annotations-for-r-for-dummies","status":"publish","type":"post","link":"https:\/\/www.portfolioprobe.com\/2012\/10\/15\/annotations-for-r-for-dummies\/","title":{"rendered":"Annotations for “R For Dummies”"},"content":{"rendered":"

Here are detailed comments on the book.\u00a0 Elsewhere there is a review of the book<\/a>.<\/p>\n

How to read R For Dummies<\/em><\/h2>\n

In order to learn R you need to do something with it.\u00a0 After you have read a little of the book, find something to do.\u00a0 Mix reading and doing your project.<\/p>\n

You cannot win if you do not play.<\/p>\n

Two complementary documents<\/h2>\n

They are also complimentary.<\/p>\n

Some hints for the R beginner<\/h3>\n

“Some hints for the R beginner”<\/a> is\u00a0 a set of pages that give you the basics of the R language.\u00a0 It is a completely different approach to the one R For Dummies<\/em> takes — you may want to investigate it.<\/p>\n

The R Inferno<\/em><\/h3>\n

If you are just at the beginning of learning R, you should ignore The R Inferno<\/em><\/a> (except perhaps Circle 1).<\/p>\n

When you start using R for real and<\/strong> run into problems, that is the time to pick it up and see if it helps.<\/p>\n

Missing piece<\/h2>\n

There is one thing that I think is missing in R For Dummies<\/em>.\u00a0 Actually it isn’t missing, it comes at the very end while I think it should be at the start.<\/p>\n

That piece is the search<\/code> function.\u00a0 More specifically the way that R operates that is highlighted by the results of the search<\/code> function.<\/p>\n

The start of “Some hints for the R beginner”<\/a> talks about search<\/code> and how R finds objects.<\/p>\n

How to use these annotations<\/h2>\n

first learning<\/h4>\n

If you are new to R and first reading the book, then you should probably mostly ignore my comments.\u00a0 However, when you are confused by something in the book, you can look to see if there is a comment on that page that pertains to what you are confused about.<\/p>\n

revising<\/h4>\n

On further reading, these comments are more likely to be of use.\u00a0 Some are clarifications, some are extensions.<\/p>\n

Page by page comments<\/h2>\n

These comments are based on the first printing.<\/p>\n

Page 10<\/h3>\n

There is more history in the Inferno-ish R presentation<\/a>.<\/p>\n

Page 11<\/h3>\n

distribution<\/h4>\n

I’m not a lawyer, but I think the phrasing about redistribution is not right.\u00a0 I think it should say “change and<\/strong> redistribute” rather than “change or redistribute”.<\/p>\n

If what you do never leaves your entity, then you can do absolutely whatever you want.\u00a0 That is the free as in speech part.\u00a0 Legalities only come into play if what you do is made available to others.\u00a0 It is a common misunderstanding that you are restricted in what you do within your own world.<\/p>\n

runs anywhere<\/h4>\n

The book highlights that R runs on many operating systems.\u00a0 It fails to make clear that the objects that it creates on the operating systems are all the same.\u00a0 You can start a project on a Linux machine at work, continue it while you commute with your Mac laptop, and then finish it on your Windows machine at home.\u00a0 No problem.<\/p>\n

Page 12<\/h3>\n

The book should tell you not to be afraid of new words.\u00a0 New words like “vector”.\u00a0 You don’t need to make friends with them right away, but don’t be scared off.<\/p>\n

(technical<\/strong>) Unhappily the word “vector” in R has several meanings — so it is unfortunate that it is the first new word.\u00a0 The meaning used throughout the book is the most common meaning.\u00a0 See The R Inferno<\/a><\/em> (Circle 5.1) for the gory details.<\/p>\n

Page 13<\/h3>\n

statistics<\/h4>\n

Pretty much everywhere in the book where it says “statistics” I would prefer “data analysis” instead.\u00a0 Statistics in many people’s mind is formal and academic, not like what they do.\u00a0 More people can feel comfortable doing data analysis than statistics.<\/p>\n

In addition to the fear factor, there really is a (slight) difference between data analysis and statistics.\u00a0 I think data analysis is more important even though I’m trained as a statistician.<\/p>\n

fields of study<\/h4>\n

There are additional fields of study where R is used that are not considered to be data hotbeds, such as music and literature.\u00a0 The flexibility of R becomes very important for data in non-traditional forms.<\/p>\n

Page 23<\/h3>\n

vectors<\/h4>\n

If you are new to R, you shouldn’t expect yourself to understand this discussion.\u00a0 Just let it sink in over time.<\/p>\n

Page 24<\/h3>\n

assignment operator<\/h4>\n

Always put spaces around the assignment operator. That makes the code much more readable.<\/p>\n

The book tells you on page 63 that you can use =<\/code> as well.\u00a0 You will see both used.\u00a0 They are mostly the same (differences are explained in The R Inferno<\/em>, Circle 8.2.26).\u00a0 I agree with the book’s approach to use <-<\/code> but really you can use either.<\/p>\n

Page 28<\/h3>\n

RStudio<\/h4>\n

A nice feature of the RStudio workspace view is that it categorizes the objects.<\/p>\n

Page 29<\/h3>\n

Windows pathnames (technical)<\/h4>\n

The book implies that you can not write Windows pathnames with backslashes.\u00a0 Actually you can, you just need to put a double backslash where you want a backslash.\u00a0 Hence it is easier and (often) less confusing to use slashes rather than backslashes.<\/p>\n

Page 30<\/h3>\n

loading objects (technical)<\/h4>\n

It is possible to use attach<\/code> instead of load<\/code>.\u00a0 If you load an object, then it is put into your global environment.\u00a0 If you attach an object, it is put separately on the search list.\u00a0 If you modify an object that has been attached, then the modified version goes into your global environment.<\/p>\n

Page 32<\/h3>\n

vectorization<\/h4>\n

There are different forms of vectorization, and the book doesn’t make that explicit.\u00a0 Vectorization can be put into three categories:<\/p>\n