Variables in Python are used by programmers to store values. These values complete a task within a program. In game design variables can track scores, count the number of turns, or store player answers. However, they have many other uses. When teaching coding to kids, it is important that the purpose of a variable is understood.
What Are Variables in Python?
A variable stores a value that can change. It is saved in a special spot that is like a numbered storage bin. When the program needs the value in the variable it takes it from the bin.
A variable can store lots of different types of information. For example, the value could be a number, text, or a list of items. In programming, a number is called an integer or int for short. Text is called a string or str for short.
A variable has two parts – name and value. To create a variable, you write the variable name, then an = symbol, followed by the variable value. For example: player=”Alex”
Variables in Python Must Have Meaningful Names
Naming a variable is a fundamental skill. A programmer should be able to read the variable name and understand its use within the program. It is very important that it is short but concise. It’s name should describe its purpose.
A Python variable must:
- be meaningful
- be one word
- have no spaces
- use no symbols
- not be a reserved Python word
Why Use a Variable?
Variables make a program flexible. Programmers use them for many reasons.
Variables Can Count the Number of Times an Event Occurs
Variables can count. This is useful when making a timer or tracking a player’s score. To count, you can create a variable called count=0. Each time the line of code count=count+1 is run than the value of the variable goes up by one.
Variables Can Store Multiple Values as a List
Variables can store more than one value. The list may look like this: pickcolor=(“red”, “blue”, “green”). By assigning multiple values to a variable it allows a program to make a choice. This use of variables creates games that are fun to play because the selection is unknown.
Variables Allow the User to Input Information
Sometimes the programmer assigns the value of a variable. Other times, the user inputs a value. This is done by prompting the user to enter data by displaying a text box or question on the screen. For example, the following code will store a user’s name:
name=input(“What is your name?”)
Variables Report Information
By using the variable name in a sentence you can report important information to the user. For instance, to display a player’s score the following code will join text with the variable value:
print(“The game is over. Your score is ” +str(score)).
Variables Personalize the User’s Experience
Variables can be used to communicate, making a device seem more human or less machine-like. Suppose that a player types in their name. Lines of code can have the computer give a personal greeting, such as Hello Sara. The sentence and variable are put together using this Python code: print(“Hello ” +str(player)).
Variables Can Trigger an Action
A variable’s value can change. If it is a number, it can get higher or lower. If it is a text, it could have another value assigned to it. Conditional logic can be used to trigger an action when a variable meets a specific condition. The value of the variable might need to be equal to, greater than, less than, or does not equal. When the variable value matches the condition, then an action will occur. The code might start like this if guess==”answer”:
Variables Calculate Amounts
Variables can be used in mathematical formulas. This has many practical applications. For example, a business owner can track employee earnings. The variables wage, hours_worked, and earnings can be placed into the formula earnings=wage*hours_worked.
Create Artwork and Build Games using Variables in Python to Teach Coding
Learning how to use variables in Python can be fun. In TechnoTurtle, the programming activities gradually introduce elementary and middle school students to variables. In this project they use variables to count loops and create spirographs that are random colors. As well, they store player answers to build a Mad Lib word game, a carnival game that awards a prize, and a guessing game. These programming tasks make the purpose of a variable easy to understand. Beginners experience first-hand how variables are used in a program to complete a task.