Now that we’ve learned what variables are, let’s learn to create and use them.
When creating variables, some computer languages require us to declare them, others create them automatically. For example:
- Java requires variables to be declared.
- Python doesn’t require variables to be declared.
When we declare a variable, we specify a variable name, additional information like the data type, and sometimes the initial value.
In Java a variable declaration looks like this:
int points;
In Python, we can create a ‘points’ variable and assign it a value of twenty like this:
points = 20
As the game is played and the user wins points, we can update the points, reassigning the variable’s value:
points = points + 100
And if we want to print out the points at the end of the game, we can retrieve the variable’s value using its name:
print(points) # Outputs 120
This is perfect for counting and printing the points. However, variables are often used to store the values of complex calculations and in the next exercise we will learn about using expressions for calculations!
Instructions
For this exercise, we don’t have enough blocks to move Codey to the goal with only the move
commands! Assign variables such as goalPositionX
or moveDistance
values by combining the teal number block with the set
command. Select different variables using the dropdown menu on the set command. Play with the following variables:
goalPositionX
to move the horizontal position of the goal (See the starting value on the grid)goalPositionY
to move the vertical position of the goalmoveDistance
to change how far Codey goes in the nextmove
command (Starts at 1)
There are many ways to solve this puzzle; try exploring!
Hint
- Try moving the goal position closer to Codey
- Try increasing the
moveDistance
to make Codey go farther with each move command
Solution
One possible solution
Set moveDistance to 5 Move Right Move Down