sibyvt

> data(iris)
> head(iris)
 Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
2          4.9         3.0          1.4         0.2  setosa
3          4.7         3.2          1.3         0.2  setosa
4          4.6         3.1          1.5         0.2  setosa
5          5.0         3.6          1.4         0.2  setosa
6          5.4         3.9          1.7         0.4  setosa
> x <- matrix(rnorm(750), 150, 5)

sibyvt

| In this lesson, we will explore some basic building blocks of the R
| programming language.

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| If at any point you'd like more information on a particular topic related to

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| In this lesson, you'll learn how to examine your local workspace in R and
| begin to explore the relationship between your workspace and the file system
| of your machine.
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| Because different operating systems have different conventions with regards
| to things like file paths, the outputs of these commands may vary across
| machines.

sibyvt

| In this lesson, you'll learn how to create sequences of numbers in R.

...swirl(0)


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| The simplest way to create a sequence of numbers in R is by using the `:`
| operator. Type 1:20 to see how it works.

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| The simplest and most common data structure in R is the vector.

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| Missing values play an important role in statistics and data analysis. Often,
| missing values must not be ignored, but rather they should be carefully
| studied to see if there's an underlying pattern or cause for their
| missingness.

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| In this lesson, you'll learn how to use lapply() and sapply(), the two most
| important members of R's *apply family of functions, also known as loop
| functions.

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| In this lesson, we'll see how to extract elements from a vector based on some
| conditions that we specify.

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election: 7


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| In this lesson, we'll cover matrices and data frames. Both represent
| 'rectangular' data types, meaning that they are used to store tabular data,
| with rows and columns.

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Selection: 11


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| In the last lesson, you learned about the two most fundamental members of R's
| *apply family of functions: lapply() and sapply(). Both take a list as input,
| apply a function to each element of the list, then combine and return the
| result. lapply() always returns a list, whereas sapply() attempts to simplify