Logical operators in Python are easy �

PROFESSOR: All right.

Another day, another video.

In this topic, I'm going to
explain logical operators.

Logical operators are used
on conditional statements

such as an if statement.

There's three types
we'll talk about--

AND, OR, NOT.

Each exhibits
different behavior,

and we'll check to
see if two or more

conditions are true, or checks
if at least one condition is

true.

NOT is a little different.

NOT will change the
result of a condition.

If a condition is
true, it's now false.

If it was originally
false, it's now true.

Here's an example.

Say we have a program to
check the temperature.

Temp equals 25.

The temperature will be in
Celsius in this example.

If the temperature falls
within a certain range,

I would like to
print a message that

says the temperature is good.

I can check more
than one condition

using the AND logical operator.

Let's check if our temperature
falls between the range

of between 0 and 30.

If temp is greater than 0
and temp is less than 30,

then we will print the
temperature is good.

If this condition is true
and this condition is true,

then we will execute this code.

Else we will print the
temperature is bad.

Our temp is currently 25.

The temperature is good.

What if it was negative
10 degrees Celsius?

Well, the temperature is bad.

What if it was over 30,
like 40 degrees Celsius?

Well, then the
temperature is still bad.

Using an AND logical operator.

If one of these
conditions is false,

then this entire statement
will evaluate to be false.

We would then skip over any
sub-code and continue on.

Using the AND logical
operator is pretty convenient

if you need to check
to see if something

is within a certain
range, like a temperature.

There is another way
we can write this, too,

using the OR logical operator.

Let's replace AND with OR.

If at least one of these
conditions is true,

then the entire
statement is true.

How about if temp is less
than or equal to 0, or if temp

is greater than or equal to 30?

Then the temperature is bad,
else the temperature is good.

Currently, our
temperature is set to 40.

Well, the temperature is bad.

This is false, but this is true.

Using the OR logical operator,
only one of these conditions

needs to be true.

If our temperature
was negative 15, well,

the temperature is still bad.

But if it was 20, well, then
the temperature is good.

AND, as well as OR,
are fairly similar.

With AND, two or
more conditions need

to be true for the
statement to be true.

With OR only, one of
them needs to be true.

Is this true, or is this true?

Now, NOT is a little different.

Let's say we have a Boolean
variable named sunny.

Is it sunny outside?

I'll set this to be true
using an if statement

if sunny is equal to true.

But if you're working
with a Boolean,

you can just shorten this
to the Boolean itself.

If sunny, then print
it is sunny outside.

Else, print it is
cloudy outside.

Sunny is set to true.

Therefore, it is sunny outside.

If sunny were set to false,
it is cloudy outside.

Using the NOT logical operator
that would flip the result.

So if not sunny, then
it is cloudy outside.

Else, it is sunny outside.

Sunny is set to false.

It is cloudy outside.

If sunny were true, well,
then it's sunny outside.

The NOT logical operator
will change something

that's true to be false.

Or if it was originally
false, it's now true.

All right, everybody.

So those are logical operators.

They're used with
conditional statements.

There's AND, OR, NOT.

We'll have more practice
with these in the future.

And yeah, those are a few
logical operators in Python.