3.1 Daily Video 1 Notes
Notes on AP Classroom
- Variables and Assignments
- Essential Knowledge:
- What is a variable
- An example naming variables
- Data Type examples
- Practice
- Possible Hacks
Variables and Assignments
Essential Knowledge:
- A variable is an abstraction inside a program that can hold a value. Each variable has associated data storage that represents one value at a time, but that value can be a list or other collection that in turn contains multiple values.
- Using meaningful variable names helps with readability of program code and understanding of what values are represented by the variables.
- Some programming languages provide types to represent data, which are referenced using variables. These types include numbers, Booleans, lists, and strings.
- Some values are better suited to representation using one type of datum rather than another.
What is a variable
- An abstraction inside a program that can hold a value
An example naming variables
- You want to store the highest score you scored in a game. So, you want to call this variable highScore
- You want to store a name, so you can call the variable firstName
- It is also possible to store true or false in a variable. For example, the variable could be called isSunny, where true and false are stored in the variable.
- phoneNumber could be a variable that stores phone numbers.
- These examples are short and convenient as opposed to a long description
- However, they give insight to the basic goal of the variable.
- Spaces also cause a problem because it is not allowed
- Dashes and numbers are also less ideal.
Data Type examples
- highScore –> an integer
- probably doing addition or subtraction, save it as an integer or numbers.
- firstName –> text(or string)
- since a name is text, it should be saved as a string
- isSunny –> boolean
- only gives two options: true or false within variable
- phoneNumber –> text(string)
- no math involved just a string of numbers
Practice
Question: What would be the best variable name and data type to store a user’s age in a program?
- Answer: name: age data type: integer Q: What would be the best variable name and data type to store the number of students in your class?
- A: name: numStudents data type: integer to add and subtract Q: What would be the best variable name and data type to store the title of a movie?
- A: name: movieTitle data type: text(or string) Q: What would be the best variable name and data type to store if someone’s pet is a dog. A: name: isDog data type: boolean
Possible Hacks
Go through the following examples and with your table discuss the best variable name and the data type for each situation and stored variable:
- You want to store the best price for apples.
- You are storing true or false in a variable that asks if the classroom is cold.
- How do you store the ID numbers for the students in the classroom?