Booleans and null (Python)

Booleans and None

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You've seen that you can work with numbers, but there are also special values: None and booleans.

The None value

None is a value that represents an empty or invalid value, or even an error, but it's different from the number 0.

For example, me.weapon returns the weapon your leek is holding, or None if you have no weapon in hand.

You may have noticed that me.setWeapon() costs 1 TP per turn. You can limit its use to turn 1 with this condition:

You test for a None value with is None (and is not None for the opposite).

Booleans: True and False

Booleans are two values: True and False. They can be used to represent anything that can have two states, such as:

• True or false
• On or off
• Yes or no
• etc.

Examples of properties and methods that return a boolean:

• enemy.alive returns True if the entity is alive, False otherwise.
• me.canUseWeapon(enemy) returns True if you can use your weapon on the enemy.

Example: we check whether we can use our weapon on the enemy:

❓ Quiz

What can None be used for?

Representing missing information or a missing value Representing the number 0 Representing an error Representing a poor-quality program

What are booleans used for?

Representing a value with two possible states Representing a very large value

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