All language subtitles for 7. Relational and Boolean Operators

OK let's build upon where we just left off with the boolean expressions.

So now let's talk about relational operators and boolean operators.

So what do we mean when we say operator let's go ahead and just add a new section here and we'll just

say relational and boolean operators if you want.

You can go ahead and just put a new line here.

So remember we specify a new line in a function and let's say greater than let's define a variable called

greater than and let's just make that equal to seven is greater than five.

OK.

So we're using a operator here with the greater than symbol right.

And we're also using a boolean expression because when we say seven is greater than five.

Well that's going to come back with true.

And we could say less than we could say five is less than seven.

And that's also going to return true What about the greater than or equal to we can say seven is greater

than or equal to seven.

And that's going to return true as well.

And then if you can think of less than or equal to it's going to be very similar we say seven less than

or equal to seven.

And that's also going to be true.

So if we were to print all of these out which we don't have to they're all going to return back true

so there's other things that we can add in here.

So what if we bring in multiple operators.

For example we could say test and you can call this whatever you want.

So what if we say seven is greater than five and five is less than seven.

So we see here that this is true and this is true.

That would make this entire statement true so you could say true here if we were to say let's just call

this test and to we were to say seven is greater than five which is true and five is greater than seven.

Well that's not true.

So this whole statement is going to be false because we're going to say and and is very important here.

Right.

What if we were to say something like or though if we were to say let's test out or we could say seven

is greater than five or five is less than seven.

Well this is going to return true and if we were to do the same thing as we did above where we say test

or two and we say seven is greater than five or five is greater than seven forgotten by parentheses

here and this is also going to return true.

Why.

Because only one statement has to be true here for these both to be true in the instance of and both

statements here have to be true in order for it to be true.

If one of them becomes false the whole thing becomes false in the sense of or the case of.

Or if both are true it's true if one or the other is true then it's true.

Both have to be false for it to actually return false.

OK so you can print these out as well to test this out.

The other thing that we can say is we could say something like test not.

We can say something like not true.

And guess what.

Not true is going to be false.

And we said not false then that will be true.

So these are the ones that can start to kind of get confusing.

So again my recommendation is to make good notes on this and then go out and study it.

And there are two false charts.

Let's just see if we can google one quickly.

There are true false charts online.

We can say True False chart by phone and go to images and we can see truth tables is what they're called.

So if A is true and B is true that a and b our true if A is false or true and B is false then they're

both false false true is false and false false is false.

So in order to have a truth table for and everything has to be true.

So if we search truth tables that might give us a better chart here and then you get something sort

of like this or you have and where you see a true true is true you have or where true false is still

true and then X or we don't have to worry about right now so take good notes on these.

Make sure you understand them.

We're going to continue to build upon them over time.

Really all you have to think about though is you have to think about boolean operators and these expressions.

And the most important things to take away from this are not just the true and false but the greater

than symbols the less than symbols.

All these different types of operators that we can utilize here and that we can also utilize things

such as and or and not as well.

So we're just adding more tools to our toolkit and more things to think about where python is important

when it comes to pen testing is not necessarily being able to develop.

And I've said this before I must say it again being able to read and understand what is going on is

super important.

Being a developer not as important.

So as long as you see these things and you see a true or you see a statement like this when you're reading

code and you say hey I know that's a boolean operator I know it's true or false.

And I kind of understand the truth tables.

Right.

So that's really what we're after here.

So as long as you start getting this understanding and comprehension that's really what we're after.

So from here we're going to move on and we're going to go into conditional statements and that is where

we get into something called if then else and we'll have a little bit of fun with those.

So I will catch you over in the next video.