Changing Variable Values

Learning Objectives Explain why a variable's value needs to change in a program. Use the assignment operator (=) to update an existing variable's value. Update a variable's value using its own current value (e.g., score = score + 10). Trace the value of a variable as it changes through a sequence of code. Predict the final output of a program where variables are updated multiple times. Differentiate between initializing a variable and updating a variable. How does a video game keep track of your score as it goes up and up? 🎮 Let's find out how variables can change! You've learned that variables are like boxes for storing information. In this lesson, we'll learn the superpower of changing what's inside those boxes after they've alread...

TermDefinitionExample VariableA named container in a program that holds a value which can change.In `score = 100`, 'score' is the variable. Assignment Operator (=)The single equals sign symbol used to give a variable a value. It tells the computer to 'assign' the value on the right to the variable on the left.The `=` in `player_name = 'Alex'` is the assignment operator. InitializationThe very first time a variable is created and given a value.`lives = 3` is the initialization of the 'lives' variable. Reassignment (Updating)Changing the value of a variable that already exists. The old value is replaced with a new one.If we have `score = 50`, and then we write `score = 75`, we have reassigned 'score'. IncrementingIncreasing the value of a nu...

Reassignment Syntax variable_name = new_value Use this to give a variable a completely new value. The computer finds the variable on the left and replaces its current value with the value on the right. Self-Referencing Update variable_name = variable_name + value This pattern is used to modify a variable based on its own current value. The computer first calculates the entire right side of the equals sign using the variable's old value, and then updates the variable with the result. Shorthand Operators variable_name += value (or -=, *=, /=) This is a shortcut for the Self-Referencing Update. `score += 10` does the exact same thing as `score = score + 10`, but it's shorter to type.