Toxic Jungle

Available Commands

Hints

• When you're using programming languages like Python, the details really matter. If you misspell one word, or if you forget even a little bit of punctuation, your code won't run!

• If you get an error, check your code closely for errors.

• To move the character one step forward, you need to type the forward() command in the coding area.

  1. Write the forward() command once more. Don't forget the parentheses!

  2. Each time you use this function, put it on on a new line.

What are Comments?

In the last programming puzzle, you wrote code for a computer to run. But humans need to read code too! We can add descriptions to our code using comments. This makes reading code a lot easier. Comments are also used to ignore some of your code to test things out or if you have code that you don't want to run at the moment.

Programmers often work together on teams, editing a single base of code, and use comments to describe their code to one another. If you're writing code with others, or want feedback from your teachers, you'll want to use comments too, so they can understand what you are trying to do.

Use comments whenever you're writing your own original Python code, too. They're also handy to remind yourself of what you were writing!

In Python, you type the pound character # to start a new comment. Any text that you write after that will be documentation for your code. In other words, it won't affect how your program runs. Here's an example.

Click on the run button to see the output.

Notice the # character can appear after your code. All the text that appears after that # won't affect the commands for the forward, turn right, forward sequence.

The comment symbol can also be used to make lines of code not run. Programmers call this commenting out their code. You can experiment with code without deleting it in this way.

In this example, we use two print functions, but only one is executed. Which statement do you think will be skipped?

Click on the run button to see this in action.

Notice how only Feather is printed. The first line is commented out, so it is not executed.

Onward and Ahead!

Available Commands

Hints

• When you're using programming languages like Python, the details really matter. If you misspell one word, or if you forget even a little bit of punctuation, your code won't run!

• If you get an error, read your code closely for errors. Make sure you don't forget the parentheses.

• To comment out a line of code, type # at the beginning of the line.

Around the Corner

Available Commands

Hints

• The turn_right() command will turn the character to the right.

U-Turn

Available Commands

Hints

• Move Feather forward() multiple times and then turn_right() once she reaches the corner.

Enemy Spotted

Available Commands

Hints

• Fire at the carnivorous plant in the way using the fire() command to get rid of it.

• Each fire() command launches an arrow that can travel up to 5 steps ahead in the direction the character is facing.

Scale the Slopes

Available Commands

Hints

• Get rid of the plants by firing an arrow at them using the fire() command.

• Each fire() command launches an arrow that can travel up to 5 steps ahead in the direction the character is facing.

• Get close before taking your shot at the second carnivorous plant. You must be at the same elevation for the arrow to hit your target

Around the Bend

Available Commands

Hints

• Use the turn_left() command when Archie reaches the corners.

Straightforward

Available Commands

What Are For Loops?

In the last puzzle, you had to write the forward() command over and over again. That was kind of annoying, wasn't it? There's an easier way to repeat code!

We'll use something called loops to run the same code many times. To start things off, let's learn about a kind of loop called the for loop.

The for loop executes the same code a certain number of times. They are useful when you need to count (e.g. count from 0 to 9).

Here's what a for loop looks like in Python code.

You can customize your for loop by adding more information to range(). The range specifier can receive up to 3 parameters, like this:

Let's count down from 9 to 0. Notice in the code how we're using the extra parameters in range().

Click on the run button to see the output.

What Is Indentation?

Did you notice that you used spaces in your for loops, for the commands you wanted to repeat? Programmers call this use of "white space" indentation.

When you're programming in Python, indentation is really important. If you don't indent your code properly, it will break or behave in unexpected ways.

Programmers use indentation to show the structure of their code and make the code more readable. You'll want to use 4 spaces to indent your code. Here's an example.

Click on the run button to see the output.

Notice how : (a colon) ends the line of code right before the indentation starts. The code inside the for loop is then indented by 4 spaces.

After the loop, you stop indenting and start coding from the beginning of the line again.

Indenting your code also makes the code much easier to read and debug.

The command (or commands) you want to repeat must be indented. Make sure you fix any other syntax issues as well!

Loop Ahead!

Available Commands

Hints

• The for loop in Python has the following syntax:

• Any code you want to repeat in your loop must be indented. All of the commands you want to repeat must be indented the same amount.

Fire, Forward, Repeat

Available Commands

Hints

• The for loop in Python has the following syntax:

• Any code you want to repeat in your loop must be indented. All of the commands you want to repeat must be indented the same amount.

Zig-Zag

Available Commands

Hints

• The format for a for loop in Python is:

• Any code you want to repeat in your loop must be indented. All of the commands you want to repeat must be indented the same amount.

Jump!

Available Commands

Hints

• The jump() command allows you to jump over the gap and land on the other side.

Jump, Forward

Available Commands

• Any code you want to repeat in your loop must be indented. All of the commands you want to repeat must be indented the same amount.

Forward, Jump

Available Commands

• Any code you want to repeat in your loop must be indented. All of the commands you want to repeat must be indented the same amount.

Jump the Gap

Available Commands

What Are Conditionals?

You can write a program so that it performs different tasks based on a condition. In this way, you can have your program "make decisions" all on its own. Conditionals are used for this purpose.

The if statement is a very common kind of conditional, so let's take a closer look.

An if statement has the following syntax:

If the condition isn't met (that is, if it is False), your program just skips right over any commands in the if statement.

For example, a condition might be i < 10.

The code inside the if statement will be executed if the value of i is less than 10.

You can also write an if statement using a condition that uses functions that return True or False. Let's consider a function called has_path_right() that returns True or False, depending on whether the path branches to the right.

Here's how we might write that out:

Path Left

Available Commands

Hints

• Check if there is a path to the left using thehas_path_left() command before turning the character to the left.

Path Right

Available Commands

Hints

• Check for a path right using the has_path_right() command before turning the character to the right.

More Turns!

Available Commands

Hints

• Check for a path left using the has_path_left() command before turning the character to the left.

• Check for a path right using the has_path_right() command before turning the character to the right.

What Is A While Loop?

We used a for loop to execute the same code for a number of times. But we have other conditional loops in Python, too.

One such conditional loop is a while loop. A while loop executes the same code again and again—as long as the specified condition is true.

The while loop has the following syntax:

The condition determines how long the loop will continue to execute. For example, you might use a condition like i < 10. This says keep those commands in the while loop running, as long as the value of i is less than 10.

Let's use a while loop to count from 0 to 9. You need to initialize the variable i = 0 outside the while loop and increment the variable using the line i +=1 at the bottom of the loop.

The condition in this case is i < 10.

Click on the run button to see it in action.

Now let's count down from 3 to 1, then have our code print something else once the while loop ends. We need to decrement the variable i at the bottom of the while loop using the line i-=1. Notice after the while block ends, there's another print().

Click on the run button to see it in action.

Add your own while loop to print all odd numbers from 0 to 20 in ascending order. Try it below.

Around the Gap

Available Commands

Hints

• Use the reached_goal() command to check if Archie has reached the pixie dust.

• Execute the loop as long the goal is not reached with the not keyword.

• Destroy the carnivorous plant using the fire() command.

• Use the enemy_in_sight() command to check if there is an enemy (carnivorous plant) within 5 steps in front of the character.

• Use the has_path_ahead() command to check if there is a path in front of the character.

Final Journey

Available Commands

Hints

• Use the is_gap_ahead() command to check if there is a gap in front of the player.