Knowledge Check

flowchart LR
    A((Objects)) --> B((Functions)) --> C((Operators))
    linkStyle default stroke:#adb5bd,stroke-width:2px

Conclusion

The core of R is creating objects using functions and operators. Before anything more advanced it is important to have a good understanding of objects, functions, and operators. You will get plenty of practice using these concepts in the other tutorials and in class.

Knowledge Check

The knowledge checks are required for each class. Wrong answers are not counted against you. Complete all questions below, then submit your results to your instructor.

What does the assignment operator <- do?

• Compares two values
• Deletes an object
• Creates an object and assigns it a value
• Prints output to the console

What is the output of the following code? x <- c(10, 20, 30) then class(x)

• “data.frame”
• “numeric”
• “character”
• “vector”

Which of the following is a valid object name in R?

• 2nd_attempt
• my variable
• budget_total
• data!set

What does str(my_data) tell you?

• The sum of all values
• Only the class of the object
• The first 6 rows
• The structure: class, dimensions, variable names, and classes

What is the result of 10 != 10 in R?

• FALSE
• TRUE
• An error
• 0

You run mean(my_df$revenue) and store the result with avg_rev <- mean(my_df$revenue). What is avg_rev?

• A function
• A dataframe
• A single numeric value (an object)
• A vector

Which operator would you use to check if city population is greater than or equal to 50,000?

• >
• ==
• >=
• !=