Write a piece of R code that you could use to teach a seven-year-old child about Boolean logic. If you have never encountered Boolean logic before (sometimes it is called Boolean algebra), you will have to look it up to discover the three essential operators (AND, OR, NOT) and how they work. In addition, you will have to discover the “operators” (i.e., the special punctuation marks) that R uses to represent Boolean operations.

### An Example: Baa-Baa Pasture

In my scenario, I want to sort sheep into different pastures based on their fleece color. Here are the coding steps that I need to accomplish this task:

1. Create R objects for sheep that define their fleece colors
2. Create R objects for pastures that define the fleece colors I want stored in the pasture
3. Write three scenarios using conditional operators (AND, OR, NOT) to return the statement “Welcome to your pasture” if the condition is TRUE and the statement “This isn’t your pasture” if the conditional is FALSE

#### Step 1: Create R objects for sheep that define their fleece colors

In R language you can assign variables to objects using <- or =. So if betty has black fleece, I can assign the color black to betty using the following expression: betty_sheep <- "black". Vocalized as “betty_sheep gets black”. Notice the quotation marks around the word black. “” helps R distinguish between characters and other objects in R.

This following code assigns the fleece color of each sheep to a unique variable:

# This code assigns the fleece color of each sheep to a unique variable
betty_sheep <- "black"
jeff_sheep <- "brown"  

After running the code above, anytime I type betty_sheep the string black is returned in the console.

#### Step 2: Create R objects for pastures that define the fleece colors

I need to define my pastures and the fleece color that each pasture will accept. In the code below, I defined two R objects (my pasture names) and their colors.

# This code assigns the color accepted in the two pastures
large_pasture <- "black"
small_pasture <- "brown" 

After running the code above, anytime I type small_pasture the string brown is returned.

#### Step 3: Three scenarios using conditional operators (AND, OR, NOT)

Sort betty_sheep AND jeff_sheep into the large_pasture using the AND operator. If both sheep fleece colors match the color in large_pasture print “Welcome to your new home,” but if both sheep fleece colors do not match the color in large_pasture print “This isn’t your home”.

This logic can be executed using a conditional expression (an if-else statement). The syntax of an if-else statement is:

if (test_expression) {
statement1
} else {
statement2
}

In Baa-Baa Pasture:

• test_expression is: betty_sheep == large_pasture & jeff_sheep == large_pasture.
• statement1 is: “Welcome to your new home”
• statement2 is: “This isn’t your home”

Note that in using the & operator, both conditional statements inside the test_expression need to be true for the entire test_expression to be true.

Now we’ll write a conditional expression (an if-else statement) that will print out the expected logic.

# AND requires both statements on either side of the operator to be true for the statement to be true

if (betty_sheep == large_pasture & jeff_sheep == large_pasture)
else print ("This isn't your pasture")
The expression on the left of test_expression betty_sheep == large_pasture is TRUE, however jeff_sheep == large_pasture is FALSE. Thus, the expression betty_sheep == large_pasture & jeff_sheep == large_pasture is FALSE since, when using AND (&), both expressions need to be TRUE in order for the entire expression to be TRUE.
Since only one of the conditionals in betty_sheep == large_pasture & jeff_sheep == large_pasture is TRUE, this means the statement is FALSE and the text “This isn’t your pasture” will be printed.