Читать книгу The Big R-Book - Philippe J. S. De Brouwer - Страница 261

1 1 According to the Tiobe-index (see https://www.tiobe.com/tiobe-index), R is the 14th most popular programming language and still on the rise.

2 2 More information can be found in this article of Hadley Wickham: https://tidyverse.tidyverse.org/articles/manifesto.html.

3 3 A notable exception here is ggplot2 This package uses operator overloading instead of piping (overloading of the + operator).

4 4 Here we use the notation package1::function1() to make clear that the function1 is the one as defined in package1.

5 5 The standard functions to read in data are covered in Section 4.8 “Selected Data Interfaces” on page 75.

6 6 Rectangular data is data that – when printed – looks like a rectangle, for example movies and pictures are not rectangular data, while a CSV file or a database table are rectangular data.

7 7 Categorical variables are variables that have a fixed and known set of possible values. These values might or might not have a (strict) order relation. For example, “sex” (M or F) would not have an order, but salary brackets might have.

8 8 Of course, if you need something else you will want to use the package that does exactly what you want. Here are some good ones that adhere largely to the tidyverse philosophy: jsonlite for JSON, xml2 for XML, httr for web APIs, rvest for web scraping, DBI for relational databases—a good resources is http://db.rstudio.com.

9 9 The lack of coherent support for the modelling and reporting area makes clear that the tidyverse is not yet a candidate to service the whole development cycle of the company yet. Modelling departments might want to have a look at the tidymodels package.tidymodels

10 10 This quote is generally attributed to the Voltaire (pen-name of Jean-Marie Arouet; 1694–1778) and is published in the French National Convention of 8 May, 1793 (see con (1793) – page 72). After that many leaders and writers of comic books have used many variants of this phrase.

11 11 R's piping operator is very similar to the piping command that youmight know fromthe most of the CLI shells of popular *nix systems where messages like the following can go a long way: dmesg | grep “Bluetooth”, though differences will appear in more complicated commands.

12 12 The function lm() generates a linear model in R of the form . More information can be found in Section 21.1 “Linear Regression” on page 375. The functions summary() and coefficients() that are used on the following pages are also explained there.