# FAQ: Data Types - Boolean

This community-built FAQ covers the “Boolean” exercise from the lesson “Data Types”.

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This exercise can be found in the following Codecademy content:

Learn How To Code

## FAQs on the exercise Boolean

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Can anyone tell me how I can input the Boolean on python to turn a system on and off. I would like SysON to be true an SysOff to be false. Would I enter it in that way or another way?

Are SystemOn and SystemOff specific commands to do something? I couldn’t find anything, so I made some up:

``````def SystemOn():
print("True, so system is now on.")

def SystemOff():
print("False, so system is now off.")

while True:
prop = input("Enter a boolean proposition, such as 3>4. \nEnter q to quit\n")
if prop == 'q':
break
is_true = (eval(prop))

if is_true:
SystemOn()
else:
SystemOff()
``````

If the user enters a statement that evaluates to True, function SystemOn() runs; if False, SystemOff() runs. The eval() function does the work.

HI, can anyone answer this question for me plz?
so, i get how we use numbers and strings, but what does exactly a boolean do?
it’s no where near clear to me !

Welcome to the forums!

A boolean can be used whenever we want to represent something that is on or off, true or false, etc. For example, what if we had a variable that represented the amount of money we had in our wallet and another variable that represented the price of a t-shirt? If we wanted to see if we had enough money to buy the t-shirt, we could store this result as a boolean. If we had enough money, we’d use true, and if not, we’d use false.

Another way booleans are very useful is in conditional statements. For example, if I have enough money, buy the t-shirt. You’ll learn more about these later in the course.

Hello.

I am curious about the example used for the boolean “lightson”

It says, " Flip the switch to see the scene change from day to night and watch the lights turn on and off. Notice how the variable `LightsOn` stays the same, but its value changes from `true` to `false’ "

[codebyte]

So why is it when the sun is out and there is daylight, the output for ‘lightson’ = false??? and vice versa for true and its night time???

Wouldn’t the daylight = true and night = false ?

Plz help.

Thank you

Welcome to the forums!

The “lights” that `lightsOn` refers to are the lights inside the house (off during the day, on at night).

Thank you for the prompt reply and the answer to something I didn’t catch LOL
Mil Gracias

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