Exercises 2 - Objects Solutions

2.1 Creating R Objects

1. The code below creates a vector of three character strings (more on vectors shortly). Use this code and the ‘storage arrow’ to create an object names adj.

c("scary","intelligent","new")

Solution:

adj <- c("scary","intelligent","new")
adj

## [1] "scary"       "intelligent" "new"

1. Similarly, create an object called nouns using the storage arrow and code below.

c("bugs", "beings", "houses")

Solution:

nouns <- c("bugs", "beings", "houses")
nouns

## [1] "bugs"   "beings" "houses"

1. The paste() function is useful for combining character strings. After completing the above parts, run the following:

paste(adj, nouns)

## [1] "scary bugs"         "intelligent beings" "new houses"

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2.2 Investigating Objects

1. iris is a built-in R object (that means you have it in your environment even if it doesn’t show it). Determine the class and structure (str) of the iris object.

Solution:

class(iris)

## [1] "data.frame"

str(iris)

## 'data.frame':    150 obs. of  5 variables:
##  $ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##  $ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##  $ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##  $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##  $ Species     : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...

1. Run the code below to create a quick visual of this dataset. Note that R is determining what to do with the plot() function based on the object given to it!

plot(iris)

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