Answer the following by constructing appropriate R commands and/or giving a text narrative.
Show that names with different capitalization refer to different objects.
age = 21
Age = "The 21st century"
age
## [1] 21
Age
## [1] "The 21st century"
The name of the object being assigned to always goes to the left of the = operator. What happens if you put it on the right?
x = 1 + 2
x
## [1] 3
1 + 2 = y
## Error: object 'y' not found
y
## Error: object 'y' not found
Show that a string and a name are different.
a = "thisisfun"
thisisfun = 7
a
## [1] "thisisfun"
thisisfun
## [1] 7
Assign a string value to an object.
x = "This is fun"
x
## [1] "This is fun"
Use scientific notation to create these numbers: 100, 10, 0.001
100
## [1] 100
10
## [1] 10
0.001
## [1] 0.001
Try these mathematical operations and explain what the values mean:
1/0
## [1] Inf
Inf represents infinity, which is created when a non-zero number is divided by 0.
0/0
## [1] NaN
NaN means 'Not a Number', and is created when a equation has impossible values.
sqrt(-3)
## Warning: NaNs produced
## [1] NaN
What's the difference between NaN and NA?
'NaN' is used exclusively for numerical operations, but NA is used for things besides numbers.
Show that the order of unnamed arguments makes a difference. Use seq() to illustrate this.
seq(1:5)
## [1] 1 2 3 4 5
seq(1:10)
## [1] 1 2 3 4 5 6 7 8 9 10
Find the names of the arguments to seq(). Show that when you use the names, the order doesn't matter.
f = seq(1:5)
g = seq(2, 10, 2)
What kind of object is created by date()?
typeof(date())
## [1] "character"
Read in the data set “utilities.csv” with fetchData("utilities.csv")
utilities = fetchData("utilities.csv")
## Retrieving from http://www.mosaic-web.org/go/datasets/utilities.csv
How many rows are there?
nrow(utilities)
## [1] 99
What are the names of the variables?
names(utilities)
## [1] "month" "day" "year" "temp"
## [5] "kwh" "ccf" "thermsPerDay" "dur"
## [9] "totalbill" "gasbill" "elecbill" "notes"
Write the Markdown to reproduce this outline. See below for a hint.
Hint:
### Fruits
1. Sweet
* Apples