Ruby Programming Tutorial - 15 - Comparison Operators Video Lecture | Introduction to Coding with Ruby - Back-End Programming

all righty guys welcome to your 15th
Ruby tutorial and in this lesson I want
to talk to you guys about the different
kinds of tests or the different types of
comparison operators that you can have
so you know before that we had this test
that says if weight is less than 150
well a less than isn't the only test
that you can have you can also have let
me go ahead and get my cursor right you
can also have greater than so if their
weight was greater than 150 then this
would be true you can also have equals
to I want to talk to you guys whenever
you're writing the equals to test you
write two equal signs a lot of people a
lot of beginners always have one equal
sign but this isn't the correct way to
do it the only time in Ruby programming
when you ever use one equal sign is when
you're assigning a value to a variable
such as the case when weight equals 600
whenever you want to test two values
such as test whether weight is equal to
150 you use two equal signs so just
remember that two equal signs is for
testing and one equal sign is for
assigning values to variables so what
this is going to do is it's going to say
okay is weight exactly equal to 150 if
it's 149 if it's 151 it's not going to
work it's going to be false the only
time this test is going to be true if
weight equals 150 and in this case where
weight goes 600 if we go ahead and run
this it's going to be false so nothing
gets outputted on another test go ahead
and move my cursor again is greater than
or equal to so in this case if the
weight is greater than or equal to for
example 150 or greater then this is
going to be true and then of course you
have less than or equal to and the last
thing is not equal to so basically this
test basically means the exact opposite
of equal to so whenever we have equal
equal the weight must equal 150 exactly
whenever we have weight explanation
point equal to this means way
not equal to basically if the weight is
anything but 150 then this test is going
to be true so let's go ahead and let me
go ahead and code something real quick
um you do not weigh 200 pounds if weight
is not equal to 200 so let's go ahead
and run this and see what we get it says
you do not weigh 200 pounds and that is
because our weight is 600 but what if we
go ahead and set weight equal to 200
well then
whenever we run this code you do not
wait 200 pounds if weight is not equal
to 200 then it says nothing that is
because our weight is equal to 200
therefore this test was not true and our
code did not run so there you go there
is all of your comparison operators and
now that I have some time left I might
as well teach you guys about one more
thing and that's the double ampersand
sign now this little key is above the
seven on your keyboard and this is what
you use whenever you want to test more
than one condition
so by condition I just mean a test
weight is not equal to 200 is a test
weight is less than 150 is a test but
what if you wanted to test multiple
tests at once well let me go ahead and
show you guys an example let's go ahead
and set our person's weight equal to 170
pounds oops I forgot to put equal sign
and that's what happens when you don't
put equal sign so now let me do it
properly weight equals 170 so just
remember that our person weighs or we
can just say that I weigh 170 pounds now
we want to run the test and we just want
output on the screen you are healthy if
not only it does the weight have to be
greater than 100 but say the healthy
range is from 100 to 300 pounds we're
being very generous generous here so not
only does your weight need to be greater
than 100 pounds but also we want to run
an additional test
and your weight needs to be what I say
weight needs to be less than 300 so what
it's going to do is it's going to test
both of these things is your weight
greater than 100 and is your weight less
than 300 if so output on the screen you
are healthy so let's run enter and see
what we get it says we are healthy
because our weight was 170 pounds it was
in the healthy range so again just
remember this whenever you want to test
multiple tests you need to join them
with a double ampersand sign the sign
above the seven on your keyboard so
let's say that the weight was actually
600 this obviously is not healthy for
any human being no matter who you are so
now whenever you run this test check it
out is the weight greater than 100 well
yes it is so this test pass but is the
weight less than 300 no so it's going to
make both of these tests it's going to
try them even though this one was true
this one was false so it's not an output
you are healthy so go ahead and hit
enter and it says no without outputting
anything so again just remember that
whenever you have multiple tests using
them with a double ampersand sign both
of the tests need to be true in order
for you to run the goat they say run to
code run the code if one of those or
both of those are false then it's not
going to run so there you have it that
is how you use on multiple comparison
operators and multiple tests using the
double ampersand hopefully you guys
understand now so in the next tutorial
I'm not even going to tell you guys you
guys are just going to have to watch
because it's going to be awesome
but for now thank you guys for watching
don't forget subscribe and I'll see you
guys later