A basic concept in (statistical) programming is called a variable.
A variable allows you to store a value (e.g. 4) or an object (e.g. a function description) in R.
You can then later use this variable's name to easily access the value or the object that is stored within this variable.
You can assign a value 4 to a variable my_var with the command
my_var <- 4
Over to you: complete the code such that it assigns the value 42 to the variable x. Submit the answer. Notice that when you ask R to print x, the value 42 appears.
# Assign the value 42 to x
x <- 42
# Print out the value of the variable x
x
> X <- 42
> X
[1] 42
Suppose you have a fruit basket with five apples. As a data analyst, you want to store the number of apples in a variable with the name my_apples.
Type the following code in an editor: my_apples <- 5. This will assign the value 5 to my_apples.
Type: my_apples below the second comment. This will print out the value of my_apples.
Submit your answer, and look at the output: you see that the number 5 is printed. So R now links the variable my_apples to the value 5.
# Assign the value 5 to the variable my_apples
my_apples <- 5
# Print out the value of the variable my_apples
my_apples
Every tasty fruit basket needs oranges, so you decide to add six oranges. As a data analyst, your reflex is to immediately create the variable my_oranges and assign the value 6 to it.
Next, you want to calculate how many pieces of fruit you have in total. Since you have given meaningful names to these values, you can now code this in a clear way:
my_apples + my_oranges
Assign to my_oranges the value 6.
Add the variables my_apples and my_oranges and have R simply print the result.
Assign the result of adding my_apples and my_oranges to a new variable my_fruit.
# Assign a value to the variables my_apples and my_oranges
my_apples <- 5
my_oranges <- 6
# Add these two variables together
my_apples + my_oranges
# Create the variable my_fruit
my_fruit <- my_apples + my_oranges
> my_apples <- 5
> my_oranges <- 6
> my_apples + my_oranges
[1] 11
> my_fruit = my_apples + my_oranges
> my_fruit
[1] 11
Common knowledge tells you not to add apples and oranges. But hey, that is what you just did, no :-)? The my_apples and my_oranges variables both contained a number in the previous exercise. The + operator works with numeric variables in R.
If you really tried to add "apples" and "oranges", and assigned a text value to the variable my_oranges, you would be trying to assign the addition of a numeric and a character variable to the variable my_fruit.
This is not possible.
Submit the answer and read the error message. Make sure to understand why this did not work.
Adjust the code so that R knows you have 6 oranges and thus a fruit basket with 11 pieces of fruit.
# Assign a value to the variable my_apples
my_apples <- 5
# Fix the assignment of my_oranges
my_oranges <- "six"
# Create the variable my_fruit and print it out
my_fruit <- my_apples + my_oranges
my_fruit
`Error: non-numeric argument to binary operator`
> my_apples <- 5
> my_oranges <- "six"
> my_apples + my_oranges
Error in my_apples + my_oranges : non-numeric argument to binary operator
> my_fruit = my_apples + my_oranges
Error in my_apples + my_oranges : non-numeric argument to binary operator
> my_fruit
[1] 11
After Variables, We are going to learn about Different Data types