Error
Errors:
5 points
Write a program to have Karel pick up her first piece of trash! Direct Karel to move to the tennis ball, pick it up, and then move one more time.
Take a moment to explore this example and familiarize yourself with the code editor:
- Press “Run” to see the program run. Follow along with the yellow highlight as Karel executes each command.
- Click “Reset” to see what it means for the program to reset.
- Click on the Left, Pause, and Right arrow to see how you can step through the program.
- Try changing the speed by sliding the bar between the turtle and the hare.
Ending World
Karel's Built in Commands
move() |
turn_left() |
|
put_ball() |
take_ball() |
UltraKarel commands
paint(color) |
UltraKarel conditions
random_chance() |
color_is(color) |
# Paints a square red. paint(color['red']) # Colors: color['red'] color['blue'] color['green'] color['yellow'] color['cyan'] color['orange'] color['white'] color['black'] color['gray'] color['purple'] # Determine if a square is a certain color if color_is(color['red']): move() Random # Returns true 50% of the time random_chance() # Returns true probability percentage of the time random_chance(probability) # Returns true 20% of the time. random_chance(0.2) # Example if random_chance(0.8): put_ball()
Functions
Writing a function is like teaching karel a new word.
Naming Functions: You can name your functions whatever you want, but you can't have spaces in the function name.
Remember that commands in functions must be indented one level
def turn_right(): turn_left() turn_left() turn_left() def turn_around(): turn_left() turn_left() def your_function_name(): # Code that will run when you make a call to # this function.
Calling a Function
You call a function to tell the computer to actually carry out the new command.
# Call the turnn_around() function once turn_around() # Call the turn_right() function 2 times turn_right() turn_right()
Conditional Statements
Remember that comands in conditional statements must be indented one level.if condition:
#code that will run if the condition is true
if condition:
#code that will run if the condition is true
else:
#code that will run if condition is not true
Example of if statements
if front_is_clear(): move() if balls_present(): take_ball() else: move()
Karel Conditions
Don't forget the() at the end!
front_is_clear() left_is_clear() right_is_clear() facing_north() facing_south() facing_east() facing_west() balls_present() |
front_is_blocked() left_is_blocked() right_is_blocked() not_facing_north() not_facing_south() not_facing_east() not_facing_west() no_balls_present() |
Loops
Remember that commands in a loop statement must be indented one level.While Loops
while CONDITION: # Code that will run while the CONDITION is true. # Once the CONDITION is no longer true, # it will stop.
Example of while loops
# This moves Karel to a wall while front_is_clear(): move()
For Loops
for i in range(COUNT): # Code that will run 'COUNT' times
Example of for loops
# This puts down 10 balls */ for i in range(10): put_ball()You can have multiple statements or function calls in a for loop.
# This puts down five balls and moves after each one for i in range(5): put_ball() move()
Use for-loops when you want to repeat something a fixed number of times.
Use while-loops when you want to repeat something as long as a condition is true.
Comments
""" A multi-line comment describes your code to someone who is reading it. """ # Use single line comments to clarify code.